Labor's improving trend in published opinion polls has continued with a new major newspaper survey suggesting the Rudd government and the Coalition have moved to level pegging on a two party preferred basis.

The Nielsen poll published in Fairfax newspapers this morning has the two party preferred measure at 50-50, and it also records a ten point bounce in Labor's primary vote since Kevin Rudd returned to the Labor leadership late last month.

Labor's primary vote is now on 39%, up from the 29% recorded just before Rudd and his caucus supporters moved against the former leader Julia Gillard during the final parliamentary sitting fortnight.

Rudd is also significantly ahead on Nielsen's preferred prime minister measure. Rudd is on 55% - a 14 point improvement compared to the last result recorded for Gillard on 17 June. Opposition leader Tony Abbott is on 41%, a nine point drop since the last survey.

The positive Nielsen result is consistent with another major opinion poll taken over this past week. A ReachTel poll of Queensland 1,613 voters commissioned for the Working for Queenslanders campaign also had Labor's primary vote in the federal contest at 40% since the leadership change. That state-based poll indicated Labor could pick up six federal seats in Queensland if an election was held now.

The positive poll trend for Labor comes as the government prepares to unveil major policy shifts this week on the clean energy package and on the management of asylum seekers. The government confirmed over the weekend that it intends to scrap the fixed price period of the carbon package, moving to an emissions trading scheme from 1 July 2014 - one year earlier than legislated.

Treasurer Chris Bowen conceded the looming policy shift would have a significant impact on the budget bottomline, and would require spending cuts. "There is a substantial impact on the budget of doing this, of course there is, and it is several billion dollars," Bowen told the Ten Network on Sunday.

Bowen said the government intended to keep the current household assistance program intact, but signalled industry assistance would be "calibrated" in light of the new arrangements. Rudd told reporters in Queensland the adjustments to the package would be budget neutral.

As the Liberal Party unleashed its first round of election advertisements on the major television networks on Sunday night, one positive about the Coalition's policy agenda, one negative about Rudd; the Opposition leader blasted the imminent carbon shift from Labor.

Abbott pointed to the lack of concrete detail about the government's plans, and argued Labor was "manipulating the news by briefing things out and the news briefings aren't followed by specific announcements."

"So in effect, Kevin Rudd yet again is using the media for his own purposes and I'm surprised people allow themselves to be used in this way. But on the assumption that there is going to be a change, look, it's just another Kevin con job," Abbott said.

"He's changed its name but he hasn't abolished the tax. You will still pay and it will still hurt, it's as simple as that. Another Kevin con job. He's changed its name, he hasn't abolished the tax. You will still pay and it will still hurt."

Greens leader Christine Milne - who, with other crossbench players, helped deliver Julia Gillard's clean energy package - was also unimpressed.

Milne said the shift was about politics not policy. "Kevin Rudd is a fake on climate," the Greens leader told the ABC on Sunday. Any change Labor makes to the clean energy package will require parliamentary approval before it can be implemented.