The union representing the city's librarians says Toronto libraries could shut down as early as Sunday, as contract negotiations remain unresolved.

According to CUPE Local 4948, the union representing 2,400 library workers, the Toronto Public Library Board made unrealistic promises to the city earlier this year when it agreed to budget cutbacks.

A deadline was set on contract talks between the two groups by Ontario's Ministry of Labour last week. CUPE 4948 members can legally strike at 12:01 a.m. on March 18.

In mid-January, Mayor Rob Ford's budget was passed with a 10 per cent funding cut to libraries. Initially, Ford planned to cut $7 million from the library budget, but council later decided to cut only $3.9 from libraries.

In a press release, the union president said the TPL Board, who agreed with the budget change, "blindly followed the lead of the City of Toronto."

Maureen O'Reilly said the library board agreed to concessions that "take away the rights of part-timers to have a decent quality of life and full-time opportunities."

She says that, as a result of the city funding cuts, the library has cut 107 full-time jobs. Only 22 per cent of TPL's part-timers get benefits, she said, and most of them are women.

O'Reilly calls the negotiations "the most onerous in the history of the library."

"As long as this remains unresolved at the table, it may be very difficult for our union to reach an agreement by the deadline," she said.

The union members have been working without a contract since Jan. 1, as part of greater labour negotiations with other indoor workers in Toronto. CUPE Local 79 represents 23,000 inside workers including nurses, child care workers, ambulance dispatchers and janitors. Local 79 cannot legally strike until March 24.