Labor's new Home Affairs spokesperson Kristina Keneally has criticised Peter Dutton for allowing the number of asylum seekers arriving by plane to blow out as she defends her credentials on border security.

Labor Leader Anthony Albanese unveiled details of his frontbench on Sunday, introducing a shadow Home Affairs portfolio for the first time and appointing Senator Keneally to the role.

READ MORE Anthony Albanese announces new Labor portfolios

"As an immigrant myself, I am proud of the multicultural character of Australia, and will look to uphold, enhance and celebrate what it means to be an Australian citizen," Senator Keneally tweeted.

Home Affairs Minister Peter Dutton was quick to attack his new rival, claiming she was far from Labor's first choice for the role given her previous statements on border protection.

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"Because, when you look at all that she has said over a number of years, there couldn't be anyone less qualified in the Labor party to be the Home Affairs shadow minister," Mr Dutton told reporters on Sunday.

He said he expected Senator Keneally, who called Mr Dutton the "most toxic man in Australian politics" during the election campaign, to continue her "very spiteful, very nasty and very personal" attacks against him.

As an immigrant myself, I am proud of the multicultural character of Australia, and will look to uphold, enhance and celebrate what it means to be an Australian citizen. I look forward to working with new Shadow Minister for Multicultural Affairs, @andrewjgiles, on this effort. — Kristina Keneally (@KKeneally) June 2, 2019

The former NSW premier vowed to apply a "blow torch" to the government's border security regime and took aim at Mr Dutton over the number of asylum seekers arriving by plane, rather than boats.

“Peter Dutton has in fact allowed people smugglers to evolve their business model from using boats to using planes,” she told the Sydney Morning Herald.

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More than 81,000 people who arrived by plane have applied for asylum in the past four years, contributing to a large increase in the number of people on bridging visas.

Senator Keneally has previously expressed personal support for onshore processing and called for a royal commission into the treatment of asylum seekers on Nauru and Manus Island.

On Monday, Senator Keneally said she had grappled with the issues and concluded boat turnbacks and offshore processing were necessary, but Australia could still treat people humanely.

"That we are keeping Australians safe, but also not losing our collective national soul, not losing our collective national conscience and ensure we are treating people humanely at all time," she told ABC radio.

SBS News approached Senator Keneally for an interview but her spokesperson said she was unavailable.

On Twitter, Senator Keneally said Labor's decision to introduce the Home Affairs portfolio sent a message that it will ensure Australians are kept safe.

"Labor fully supports offshore processing, boat turnbacks where safe to do so, and regional resettlement," she tweeted.