Greens leader Bob Brown has cautiously welcomed today's Newspoll boost for his party.

The poll, published in The Australian, shows support for the Greens rising four points to a record high of 16 per cent, while support for the two main parties has slumped.

Senator Brown says the large jump could be a polling aberration, but says it is still proof the Greens are gaining ground.

"I think you can easily get carried away by one poll - mind you, I'd rather have a poll going up than the other way," he told the ABC's NewsRadio.

"We're going to continue working to give the Australian people a good alternative to both the major parties who are increasingly frustrating voters.

"We're not just blockers, we're creative people in the Senate."

Today's Newspoll comes amid an increasing brawl between Labor and the Opposition over the Government's plans to introduce a 40 per cent tax on mining.

Kevin Rudd and Tony Abbott attacked each other in Parliament yesterday for being loose with the truth and lacking credibility, but the Newspoll shows they have both lost voter support.

Only 36 per cent of voters are satisfied with Mr Rudd and 37 per cent with Mr Abbott, giving them both "negative" dissatisfaction ratings.

Labor is ahead on the two-party vote at 51 per cent to the Coalition's 49 per cent but Newspoll says that would result in a hung parliament.

Treasurer Wayne Swan has told Radio National he is not concerned by the poll result.

"We don't govern in terms of the fortnightly cycle on terms of Newspoll," he said.

"I'm not in any way worried, or whatever, about opinion polls. What we are doing is in the national interest."

Coalition frontbencher Eric Abetz has warned voters if they support the the Greens Labor will be returned to government.

"If the Australian people want to change the government they will in fact have to vote for the Coalition," he said.

"Trying to go for the Greens is simply a half-way house."

Newspoll chief executive Martin O'Shannessy says the poll shows voters are disappointed in both Mr Rudd and Mr Abbott.

"I think the bigger issue for both parties is the tremendous drop we've seen in satisfaction in both their leaders," he told AM.