The Conservative government will introduce legislation requiring Parliament to vote on plans by the Ontario and British Columbia governments to adopt the harmonized sales tax, CTV News has learned.

If the legislation fails to pass, the provincial governments will be unable to pass the HST.

The Conservatives support the HST and want the legislation passed by the holiday break. However, the legislation will not be a confidence motion, meaning the government cannot be defeated on the bill.

"(The Conservatives) are saying if it is defeated it will not be revisited, meaning the end of the harmonized sales tax in Ontario and British Columbia," CTV's Ottawa Bureau Chief Robert Fife said on Thursday night.

Politically, the move puts the federal Liberals in a difficult position.

If they support the bill, they will face criticism on the left from the NDP.

Help defeat the bill, and the provincial Liberal governments in B.C. and Ontario, may not help their federal counterparts in the next election.

Both Ontario and B.C. intend to combine the provincial sales tax with the federal GST. The HST would be 12 per cent in B.C. and 13 per cent in Ontario.

The Ontario, B.C. and federal governments say a harmonized tax will lower taxes for businesses and create more jobs.

Critics of the HST say it is a tax grab as items that were previously exempt will now be taxed.

Nova Scotia, New Brunswick and Newfoundland and Labrador already adopted the HST.