Labor has registered another disastrous opinion poll result.

The latest Nielsen survey shows Labor's primary vote has dropped to just 26%, the lowest for a major party in Nielsen's 39 year history.

The Coalition's primary vote is up two points to 51% while the Greens registered 11%.

And for the first time, opposition Leader Tony Abbott is ahead of Julia Gillard as preferred prime minister - 51% to 40%.

The PM is pressing on with her $12 million television ad campaign promoting the government's carbon tax. It began airing last night with Gillard defending the use of taxpayer money to fund them.

She says it's the right thing to do given the amount of misinformation being released by stakeholder groups, big industry and the coalition