Former B.C. premier Bill Vander Zalm is leading the provincewide initiative vote campaign to repeal the soon-to-be introduced HST. (CBC)

The organizers of B.C.'s anti-HST petition say they only have only 13 ridings left in their campaign to collect enough signatures to trigger a provincewide vote on the tax.

Fight HST head organizer Chris Delaney says the group has collected about 500,000 signatures from across the province.

"This is monumental," said Delaney.

So far, the group has collected the required 10 per cent of signatures from voters in 72 of the province's 85 ridings, leaving seven weeks to collect the remaining signatures by the July 5 deadline.

Most of the ridings where they have yet to collect the required 10 per cent of voters' signatures are in the Metro Vancouver area, including Premier Gordon Campbell's riding of Vancouver Point Grey, where petition organizers say they have collected about 2,000 of the 6,000 needed signatures.

Delaney said the group is not concerned about its low numbers in the Metro Vancouver ridings.

"Those ridings started late, and were behind in previous reports. Now, they are not only catching up, but are tracking faster than the majority of other ridings did during their peaks," he said in a statement released Monday by Fight HST.

The Fight HST campaign's leader, former premier Bill Vander Zalm, said he was extremely encouraged by the results.

"I was out campaigning this weekend in Vancouver, Richmond and Delta, and everywhere people wanted to sign the petition. There has been no loss of interest at all, and in fact, it just seems to keep on growing. It's fantastic!" he said.

But Vander Zalm said the Metro Vancouver ridings have proven more difficult for campaigners.

"It's much more difficult to do in an urban area than in a rural area. In some small town we can set a table up anywhere and before you know it we've got a lineup a block long. In Vancouver, that's a little tougher," he said.

"For one thing, we're not allowed to go into apartments without permission of the owner and that makes it tough because many of the apartment owners are out of the country," said Vander Zalm.

Under B.C.'s Recall and Initiative Act, if the petition meets the requirements, the provincial government would have to either present a bill in the legislature that repeals the HST or hold a non-binding provincewide vote on the tax.

If the anti-HST forces win that vote, the government would then have no choice but to introduce a bill repealing the HST, although MLAs could vote it down.

With a Liberal majority in the legislature, the bill likely would not pass, but still would present a major political embarrassment to the government.

The 12 per cent HST, which combines the PST and the GST in B.C., is expected to come into effect on July 1, well before the petition could trigger any votes.