VANCOUVER -- New Democrat leader Adrian Dix is defending his party's latest commercial, saying it is merely holding the B.C. Liberals to account and isn't an attack ad.

The 30-second radio spot starts off criticizing the B.C. Liberals for mishandling the Harmonized Sales Tax, claims the Liberals broke public trust over the BC Rail sale and that they aren't being honest about deficits and debt.

But Dix says the ad merely sets the facts straight, and is different from the personal attack ads that Premier Christy Clark and the Liberals have been launching against him.

The NDP leader says he continues to run a positive campaign, and that despite the polls tightening, he is confident Liberal-held ridings such as those that he visited in the Okanagan yesterday will become NDP holdings.

He made the comments in Vancouver, where he repeated that an NDP government would ban corporate and union donations and taxpayer-funded ads, as well as launch an inquiry into the BC Rail scandal.

Dix will be campaigning throughout Metro Vancouver today, while Clark is in Burns Lake, Quesnel and Prince George.