Recent Newspoll surveys indicate the coalition is well behind Labor in every state and territory except Western Australia, and Mr Turnbull's personal popularity has taken a battering since April.

Mr Turnbull has shrugged off suggestions the OzCar scandal has further harmed his position and has promised to regain voters' trust.

"I've just got to keep on doing my job. It is a great truism in politics that the only poll that matters is the one on election day. Opinion polls go up and down," Mr Turnbull told Macquarie Radio on Friday.

"The reality is that the opinion polls are interesting to commentate on, and to the media - but the only one that matters is the one on election day.

"This is a government that has been very successful at spin, it's had one failure after another.

"The biggest failure of all is the big mountain of debt they are building up, this gigantic burden they're imposing on Australians.

"We've had cash giveaways that haven't created a single job and now we've got this scandalously mismanaged schools building program where they're rushing out $14 billion investment in school halls and libraries.

"Schools are getting very little consultation with communities.

"There needs to be a thorough investigation into the way these billions of dollars are being wasted."

Mr Turnbull also defended his role in the OzCar affair, involving a fake email that alleged Prime Minister Kevin Rudd had interfered to obtain a government benefit for a friend.

"I never raised the matter of the email, I didn't refer to it, I didn't quote from it.

"The criticism I made of the prime minister was based entirely on the sworn evidence given by the Treasury official before the Senate.

"I didn't publish an email or wave it around or refer to it.

"We will turn it around on election day, that's our commitment. We should win the next election and we will win the next election.

"If Australians want to see their economy managed in a way that will not place an intolerable burden of debt and deficit on the shoulders of their children and their children after, if they want to see their economy managed responsibly, they should vote for us."