Six babies have been infected with herpes after New York City Mayor Bill de Blasio lifted regulations on the the controversial Jewish circumcision ritual, health officials said.

The ancient Orthodox Jewish practice known as metzitzah b'peh, requires a mohel, the person performing the circumcision, to suck blood from the baby's wound.

In the most recent case, a baby was taken to the hospital after developing a rash on his genitals, buttocks, and thigh 15 days after undergoing the procedure, the city health department said in an alert Wednesday.

Ancient ritual: The ancient Orthodox Jewish practice known as metzitzah b'peh, requires a mohel, the person performing the circumcision, to suck blood from the baby's wound (stock photo)

The ritual has become controversial since its been linked to multiple cases of neonatal herpes

Doctors found the newborn had been infected with herpes simplex virus-1, more commonly known as oral herpes (HSV-1). The baby boy was hospitalized for two weeks and is now recovering.

The ultra-Orthodox ritual has become controversial because of the health risks to infants as mohels are not even required to be tested for herpes.

In 2016 two cases were linked to the ritual and three cases were reported in 2015, according to the Health Department.

Former Mayor Michael Bloomberg had implemented restrictions requiring parental consent forms to be signed before the male infants undergo the circumcision.

However, Mayor Bill de Blasio lifted the requirements in 2015 after he promised the Hasidic Jewish community to scrap rule the during his campaign.

Leaders in the Orthodox group had argued that the regulations violated their religious freedom.

Instead, de Blasio required doctors to distribute pamphlets warning parents about the risks, but health department officials said they have not been effective, the New York Post reported.

Health officials said the ritual has been linked 24 cases of herpes since 2000. Two of the infants who were infected suffered brain damaged and two died.

On Wednesday the mayor said the city in is working to identify the mohel and expects 'full cooperation from the community. '