A former employee of the Newton assessor’s office, ­accused of wrongly giving ­elderly residents a $1,000 property tax exemption, was ­arraigned Monday on charges of forgery and filing a false ­report by a public worker.

Stanley Dobies, 62, pleaded not guilty to the charges, said Stephanie Guyotte, a spokeswoman for the Middlesex district attorney’s office. If convicted, Dobies faces up to 10 years in prison, Guyotte said.

Dobies’s lawyer, Joseph ­Donnellan, declined to comment.

Dobies had been employed by the city assessor’s office since 1987 and resigned Nov. 20 as a result of the investigation, said Donnalyn Kahn, Newton’s ­solicitor.

Dobies had been on medical leave, most of it unpaid, for the past 19 months, Kahn said.

According to city officials, Dobies allegedly whited out or copied over income information in applications for an ­elderly tax exemption. Last year about six to 10 people whose ­incomes exceeded the limits received the $1,000 tax discount. The residents seemed unaware of the scheme, and it is unclear why they got the exemption, though none were exceedingly wealthy, Kahn said.

The assessor’s office is conducting an internal audit to ­determine whether the false documentation went back further than one year, Kahn said.

Newton officials discovered the discrepancy in October, and the city has increased oversight of the program, Mayor Setti Warren said. The assessor’s ­office now requires supervisors who approve tax exemptions to review all the documentation, including tax returns. Previously, the supervisor reviewed only a list of names.

Newton officials said that Dobies has filed an application to receive his public pension ­effective Nov. 30.