Montreal blue-collar workers demonstrated at city hall Wednesday during a four-hour walkout to protest the pace of contract talks, but Mayor Gerald Tremblay responded by saying he will not cave to their demands.

About 5,000 workers participated in the strike, which lasted from 10 a.m. until 2 p.m. The workers have been without a contract since August 2007. They would like to see a salary increase of 10 percent over the next four years, and seven additional statutory holidays, for a total of 15 statutory holidays per year. They also want the city to cut down on subcontracting to private companies.

Tremblay said the workers' demands would cost taxpayers up to $121 million, and the city simply cannot afford it.

"If they want to go in arbitration, they can go in arbitration, but if they think we're going to cave and give them more money ... the answer is no."

Tremblay said the workers are using the municipal election campaign to try and pressure city hall into meeting their demands.

Garbage collection and recycling pickup was delayed in some parts of Montreal because of the half-day strike, but most of the work was completed as usual because of city subcontracting.