The administration of New York City Mayor Bill de Blasio wants ritual circumcisers who use a controversial wound-cleaning method to verbally inform parents of the risks, a media report says.

The report concerns metzitzah b'peh, Hebrew for 'oral suction,' the method by which an ultra-Orthodox ritual circumciser cleans a circumcision wound by mouth.

A number of newborns have been infected with herpes and a couple have died as a result of the method, media reports say.

The previous mayoral administration, run by Michael Bloomberg, had required parents to say in writing that they understood that the city recommended against the practice.

The New York Daily News, citing sources, said the city now wants to switch to verbal assurances.

But the paper said that the plan is being held up by a group of rabbis who oppose forcing ultra-Orthodox mohelim, the rabbis who circumcise babies, to tell parents of the risks.

These rabbis oppose any accord that impinges on religious freedom, and many rabbis have questioned the scientific evidence underpinning the warnings, the paper reported.