Former B.C. deputy premier Christy Clark contends the Campbell government hid HST plans. (Craig Hodge/Canadian Press)

A former provincial deputy premier has sharply criticized B.C. Premier Gordon Campbell over his plans for introducing a harmonized sales tax.

Christy Clark told CBC News on Thursday that she thought it was "sneaky" of the Campbell government to announce the HST after the May provincial election.

Clark said it seems impossible the tax wasn't contemplated before the spring ballot.

"I just don't think it's possible that that could be the case," said Clark, who was appointed deputy premier by Campbell in 2001. She quit provincial politics in 2005.

B.C. Finance Minister Colin Hansen has said the HST was not on the Liberals' radar until after the election.

Clark said business groups and senior financial officials had recommended a harmonized sales tax for years but the Campbell government said nothing until July.

"It was quite clear the government was going to be faced with this decision in March when Ontario adopted it, and they never thought to mention it to the voting public. I mean, it's just sneaky all around and I don't think that sits well with people," Clark said.

Clark said she thinks the Campbell government really believes the new tax is good public policy but they didn't adopt it until the federal government came up with money to ease the transition.

"The combination of their sense of justice about it and the big bribe from the federal government, I believe that's what persuaded them to do it," Clark said.

B.C. would receive $1.6 billion from the federal government under a formula that provides transition funds to provinces that agree to move to a harmonized tax.

Clark said there are legitimate arguments for the HST, but the government hasn't been doing a good job of making them.

"I think it could come at a very high political cost for them," Clark said.