Hundreds of mass goers may have been exposed to  the hepatitis A virus while receiving Holy Communion at a Catholic church in Long Island on Christmas morning according to officials.

Authorities have warned that an unidentified person, who handled communion wafers may have transmitted the illness to parishioners at two separate Masses.

The incident occurred at Our Lady of Lourdes Roman Catholic Church in Massapepua during the 10:30am and 12:00pm religious services on December 25.

The Nassau County Department of Health warned anyone who may have received Holy Communion to report for inoculation at the church this week.

"Individuals may be at risk," said Sean Dolan, a spokesman for Diocese of Rockville Centre.

"It's not the Communion wafer itself," Dolan told the New York Post. "It was somebody who handled the Communion wafers. There may have been a transmission there."

When diagnosed, most people recover in a few weeks. Symptoms include fever, fatigue, poor appetite, nausea and stomach pain.

Mr Dolan said the incident was under investigation.

"We're hoping that anybody who might come down with the virus comes out and gets the vaccination, “he added.