LEWISTON – Thousands of Maine taxpayers received late tax notices this week, even though they filed returns, according to an official at the state’s revenue agency.

A computer glitch caused the mistake, said Dennis Doiron, director of the income tax division at Maine Revenue Services.

By Thursday, several hundred taxpayers had called the state agency with questions about the notices.

Doris Redmond received a letter Wednesday noting that she owed $511 in state income taxes.

Not paying taxes would be a big deal in Redmond’s profession; she’s a tax specialist for H&R Block in Augusta. But she had a canceled check proving she had paid.

Doiron said Maine residents who receive late notices should ignore them if they know they have paid their taxes.

He said the error only affected people who filed returns electronically – over the Internet, the telephone or through tax specialists.

Those taxpayers were given a printable coupon listing the amount they owed, and they had the option of paying electronically or sending a check at a later date.

The problem arose when e-filers mailed payments at the last minute, midnight April 16, Doiron said.

The state received 200,000 income tax returns on April 16. Computers were programmed to send late notices for payments that had not been tabulated by April 20. But with the huge wave of mail, many were still not tabulated.

Next year, the late-notice date will be pushed back to April 30.