SUSPECTED explosives have been detonated in Australind after a second package was found in the Leschenault Estuary yesterday.

Police evacuated the area near the jetty at the Leschenault Estuary and closed nearby roads just before the second package was detonated at 5pm.

It comes as police divers today resumed their search for the deadly explosive TATP after the second package' was found by police divers yesterday.

Officer injured from TATP

Police Commissioner Karl O'Callaghan today revealed that one of the officers who handled the deadly explosive suffered a minor chemical burn which required hospital treatment.

Army divers headed out onto Leschenault Inlet about 8.15am today and were out on the water about an hour before returning to shore shortly before 9.30am.

Police and army divers wearing snorkels appeared to be doing a sweep of the Leschenault jetty, close to where the second suspect package was found yesterday.

About 2.20pm, officers got into a 4WD and drove it along the jetty. Mr O'Callaghan confirmed that one of the police officers who handled the deadly explosive material found in Australind early this week had to be treated for a minor chemical burn to a finger.

Mr O'Callaghan and Premier Colin Barnett today sought to reassure the public they were not in any immediate danger following the discovery of the deadly explosive in the state's South West.

The pair said every precaution was being taken and that police were treating it as an extremely serious criminal investigation.

■ WHAT IS TATP?

Despite a meeting of foreign ministers in Perth today, the national terrorism alert level has not been changed. While federal investigators were involved in the inquiry, it has not been confirmed whether ASIO is involved.

Mr O'Callaghan said police still did not know what was in the package found yesterday but Army bomb experts were treating it as explosive material.

"We are treating this as a serious crime investigation and there will be detectives down there and a lot of others doing work on this for the next few days," Mr O'Callaghan said.

"It will not be a short operation. But what I can tell you is that our priority is to make sure the community is safe."

Mr O'Callaghan also defended the police procedure following the discovery of the first package saying a presumptive test carried out on the substance indicated that it was "illicit".

"The officers concerned treated that substance like any other drug," he said. "The package was transported as an illicit drug because presumptive tests indicated that it might be.

"Bear in mind drugs get cut with all different compounds. The officer followed protocol. Once it was identified of course we dealt with it as a volatile material."

Procedure concerns Police Union

The WA Police Union said today it plans to meet with the Police Commissioner to raise its concerns over the handling of Tuesday's explosives find.

WA Police Union vice president Brandon Shortland told reporters this afternoon the incident on Tuesday "had highlighted a number of concerns" to the union.

"We are going to raise those (concerns) in a formal capacity with the Commissioner," Mr Shortland said.

Mr Shortland said those concerns related to the seizure, handling and subsequent transportation of the TATP package found earlier in the week.

He added: "We don't believe that there is adequate training…our members are not chemists, they are not experts in hazardous material transportation.

"Our members did a great job under trying circumstances…unfortunately there are policies, systems and procedures that need to be looked at to ensure that explosives are not handled in that manner again."

The Premier said he wanted to reassure the local Australind community, as well as the wider public, that there was no immediate danger and that community safety was the number one consideration.

"All that is being done is what needs to be done. There is a significant operation underway involving and being led by WA Police but also involving federal agencies. Several precautionary measures will need to be taken and will be overseen by police.

"I would simply ask members of the public to co-operate with police. There is no immediate danger to anyone but all precautionary measures need to be taken."

State Crime A/Commander Scott Higgins said with the first package, confirmed to be TATP, coming from the Leschenault jetty areaand a second suspicious package found yesterday, divers had swept the jetty to make sure there were no items missed.

Terror scare a 'nasty coincidence'

Yesterday a counter-terrorism expert said the discovery of volatile explosives as world leaders met in Perth for the Indian Ocean Rim Association summit was a "nasty coincidence."

Curtin University's Alexey Muraviev told PerthNow the discovery raised additional security concerns for the event, which would see Foreign Ministers from countries such as India, Iran, Kenya, Malaysia and Sri Lanka meet in Perth today.

Dr Muraviev said terrorists wanted symbolic targets and the IORA event could provide such an opportunity.

"Many of them (member countries) are engaged in counter-terrorism efforts and many countries of the Indian Ocean Rim are affected by ongoing high levels of terrorism activity," he said.

He said because Perth was not considered a high-risk terrorism target, there would have also been an added element of surprise in any attack plot.

Police today said they were not ruling out any line of inquiry after the second suspicious package was found.

Army bomb disposal experts were called in to help dispose of explosives after the package was found in the estuary where a large cache of the volatile chemical compound TATP was discovered on Tuesday.

PerthNow understands the substance found yesterday in the water today was located at the end of the jetty, and heavily weighted.

It was similar in size to the one found on Tuesday.

Sweep of surrounding areas

Forensic police officers have scoured nearby areas of the inlet and spent 15 minutes photographing evidence on the side of Old Coast Road, about 50m from the jetty.

It appeared to be a small piece of paper which was eventually bagged and taken away as evidence by the officer.

Police say there are no "legitimate" reasons why someone would be in the possession of the highly dangerous chemical other than for criminal activities.

Following yesterday's discovery of what could be more of the highly explosive material, Acting Commander Higgins told a press conference that while police were still trying to establish what it was intended for, the substance was used in terrorist attacks.

Earlier police confirmed the material destroyed at Gloucester Park was TATP, or 'Mother of Satan', the volatile chemical used in the 2005 London bombings.

Acting Commander Higgins said police were not ruling out any line of inquiry and confirmed the Major Crime Squad was looking at a list of people but were not close to making an arrest.

He also said TATP had previously been found in other locations in Australia.

"There's a whole range of different possibilities (for why) from prank to the more sinister and those are the ones we are looking in to," he said.

"This is not an unknown material and it has been found in other locations on previous occasions.

"There's no information to indicate there is cause of concern (regarding threats).

"One of the things we are trying to work out is exactly what it was intended for and we don't know that yet. And that is the reason we are asking for the public's help."

Questioned by the Opposition in State Parliament about the risk to the public during the operation to move the original cache of TATP from the city to Gloucester Park, Mr Barnett said he would not disclose details of confidential briefings.

"This is an extremely serious situation. But it is confidential and you are not to use it politically,'' Mr Barnett said.