WINNIPEG -- Manitoba's Opposition Tories and governing New Democrats squared off over master labour agreements Tuesday, with Tory Leader Brian Pallister saying the deals will add $3 billion to the cost of the province's looming mega-projects.

Master labour agreements require all workers on a project to be governed by agreements struck with unions. The workers, whether or not they formally belong to unions, get the wages and benefits negotiated by the unions. In exchange, they pay dues while they work on the construction project.

"The fact is, many companies just won't participate in the process. This drives the cost up," Pallister told reporters.

The agreements have long been used in Manitoba and elsewhere, in part to ensure that projects aren't halted by work stoppages. The deals forbid strikes or lockouts for the length of the project.

"In this kind of environment where it's hard to get workers, and workers could go anywhere in the country, I think it's good that we have a good, stable labour environment," Dave Chomiak, the minister responsible for Manitoba Hydro, said.

Pallister, however, said some non-union companies will not bid for work on projects where their workers will essentially be forced to be part of a union. With fewer companies bidding, Pallister said taxpayers will not get the lowest price on some $22 billion in work the province has planned -- new hydroelectric generating stations, a massive transmission line and a new road to remote communities on the east side of Lake Winnipeg.

"We continue to use an antiquated approach which costs the taxpayers more," Pallister said.

Pallister's move to stake out a position on master labour agreements is his latest attempt to draw a clear distinction between his party, which he has led since July, and the NDP, which has strong support from unions.

The NDP responded, as it has since the days of Pallister's predecessor Hugh McFadyen, by accusing the Tories of being throwbacks to a different era.

"Mr. Pallister is sounding a lot more like someone from the 1940's," Chomiak said.

Master labour agreements have been used by governments of all stripes, including the Progressive Conservative Mike Harris government in Ontario for highway projects, Chomiak said.

The exchange comes as Manitoba Hydro faces a lawsuit from a non-union construction association and five workers, who want the Crown corporation to hire workers without requiring them to fall under a unions' jurisdiction.

The lawsuit, filed in June, has yet to be heard in court.