OTTAWA - Canada Post and the union representing its urban-based workers were continuing negotiations on a new collective agreement as a union-imposed strike deadline loomed, the Crown corporation said Saturday.

An earlier agreement covering some 50,000 employees expired Jan. 31, and talks on a new deal began last fall.

"Canada Post remains committed to reaching a negotiated settlement that will protect Canada's postal service, minimize future postal rate increases and improve the wages of our employees," said spokesperson Jon Hamilton.

The talks will continue throughout the long weekend, he said.

The negotiators face a Wednesday deadline that would put the two sides in a legal position for a strike or a lockout.

Major issues include wages and benefits, staffing levels and working conditions.

On Friday, federal Labour Minister Lisa Raitt urged both sides to reach a deal to avert a potential disruption of the country's mail service.

Meanwhile, Canada Post has reached an agreement with the union to bring in volunteer postal workers to deliver cheques to pensioners and those on social assistance should a labour disruption occur.