Former Socred premier Bill Vander Zalm plans a rally to launch his anti-HST campaign. (Ritchie Bros. Auctioneers Inc.)

Former B.C. premier Bill Vander Zalm says he intends to launch an anti-HST campaign with a Sept. 19 rally in Vancouver.

Vander Zalm said Tuesday he believes outrage over the merger of B.C.'s sales tax with the federal GST will translate into support for petitions against the plan.

That puts the former Social Credit premier in league with his one-time political foes — the B.C. NDP — who started a province-wide petition against the harmonized sales tax July 31.

Vander Zalm said if 10 per cent of voters in each constituency in B.C. sign the petition, the provincial government would be required to hold a referendum on the issue.

B.C. Premier Gordon Campbell and provincial Finance Minister Colin Hansen went public July 23 with the government's plans to introduce the harmonized tax in the summer of 2010.

The plan has come under criticism from consumer and business groups and from members of both of B.C.'s dominant political parties.

Last week, Campbell's former deputy premier openly criticized the B.C. Liberal government's handling of the HST issue, saying the way it was introduced was "sneaky."

Christy Clark also said province was taking "a big bribe" from the federal government, which will provide B.C. $1.6 billion in transition funding if it goes to a harmonized tax