Judith Rivera's public plea alerted officials to the crisis
The government said all 240 of the country's facilities would be thoroughly screened, amid what is being described as a national emergency.
The patients were all infected at a hospital in the port city of Callao.
Officials insisted Peru's blood banks met international standards and urged people to continue giving blood.
"We do not want people to panic, what we have to do is be more careful, strengthen our care [of patients]," said Health Minister Carlos Vallejos.
Public alarm
The crisis was prompted after 44-year-old Judith Rivera contacted the media earlier this week to say she had been infected with HIV during a routine operation.
Mrs Rivera, a mother of four, said she was taking legal action to claim compensation.
"What is done is done, as they say, and a life has no price tag," she said during a news conference.
Health officials later revealed that three other patients had been infected with the virus after having blood transfusions at the same hospital - one of them a child aged 11 months.
The Washington-based Pan American Health Organization says its latest figures show that up to a quarter of the blood in Peru's banks is not properly screened.
In a further blow to the health system, officials also confirmed that 30 patients who attended a dialysis treatment centre had been infected with Hepatitis C.
The BBC's Dan Collyns, in Lima, says Peruvians are alarmed and are avoiding public hospitals.
He says the government's response to the crisis is unlikely to restore public confidence in the country's flagging health service.
At least four people in Peru have contracted HIV, the virus that causes AIDS after receiving blood transfusions that were infected with the deadly virus.

As a result, all of Peru's 240 blood banks have been closed pending further investigation and an emergency has been declared by the government.

"This situation cannot continue. All of Peru's blood banks are being reviewed. We do not want people to panic, what we have to do is be more careful, strengthen our care," said Carlos Vallejos, the Health Minister of Peru.

The country's government made its decision when Judith Rivera, 44 and mother of four children, went public with claims that during an operation, she was infected with HIV when doctors gave her a transfusion. 

Soon after the government admitted that at least three other individuals, one being an infant child only 11 months old, another a 17 year-old boy, contracted the virus through blood transfusions and all received care from the same hospitals.

Vallejos also stated that all of the individuals infected will receive whatever care is necessary to treat their conditions.