Environment Minister Malcolm Turnbull says he has never had to compromise his principles in order to pursue his political career.

His opposite number, Labor environment spokesman Peter Garrett, says he accepts the need to be a team player in politics while denying he has betrayed his previously strident left-wing views.

Both men went head to head today during a debate on environmental policy at the National Press Club.

Mr Garrett's critics say the former Midnight Oil lead singer has had to maintain a public stance as a Labor MP that is at odds with his formerly outspoken views on issues such as uranium mining, the US alliance and logging of old-growth forests.

Asked today whether he had betrayed his principles, Mr Garrett rejected the accusation.

"I don't accept for a minute that what I'm doing as Labor's shadow minister for climate change and the environment is a betrayal of anything at all, including my principles," he said.

"I would argue strongly that it's the opposite. It's the opportunity to participate in an important forum, the parliament, in an important institution, the federal opposition, to build and to develop and to drive good environment policies."

But he accepted the need to toe the party line on key issues on occasions.

"Yes, it is the case that when you join a political party you accept that you're bound by party discipline," he said.

"I made that very clear that I accepted that when I joined the Labor Party. And as a consequence you're a team player, and being a team player means that you get on with the job at hand."

Defending Labor's support for the Tasmanian pulp mill, Mr Garrett said Labor had always been committed to value-adding in the forestry industry, so long as it was done according to environmental best practice.

"To suggest in some way that it's a betrayal of the values that I have to be a Labor shadow minister I think is stringing that bow just a little too far."

Mr Garrett said he and Mr Turnbull had both entered politics for the same reason - to make a difference - and he had chosen to run for Labor because he thought it would deliver the best environment policy for the country.

"I certainly accept that we will not satisfy all the expectations that people have of us," he said.

"Some will think we haven't gone far enough, some will think we go too far."

Mr Turnbull said Mr Garrett has had to recant a lot of his previous positions on controversial issues.

"I haven't had to do that," Mr Turnbull said.

"I can't think of any of my principles that I've had to compromise."

However, the republican Mr Turnbull said he and Prime Minister John Howard, a staunch monarchist, had agreed to disagree on whether Australia should become a republic.

Mr Turnbull said compromises were sometimes necessary in politics.

"In a government and in a society, compromise is part of the business of getting things done," he said.

"So you've got to draw a distinction, I think, between what you might call issues of principle and then issues relating to how you actually get things done."

Poll rates Garrett over Turnbull on climate change

Voters in marginal seats believe Mr Garrett - despite his election campaign gaffes - is more serious about tackling global warming than his Coalition opponents, a new survey finds.

The survey also found three-quarters of those polled backed a position on a new global carbon-emissions treaty that Mr Garrett was forced to abandon last week.

The survey, commissioned by the Climate Institute, found 43 per cent of the voters thought Mr Garrett "very serious" about climate change, compared with only 7 per cent for Mr Turnbull.

Twenty-eight per cent thought the same of Labor leader Kevin Rudd, 11 per cent of Mr Howard and 6 per cent of federal Treasurer Peter Costello.

Seventy-five per cent thought Australia should commit to greenhouse pollution targets rather than wait for the developing world to act - a position Mr Garrett initially endorsed last week.

Later, his stance changed to requiring commitments from developing countries, prompting Mr Howard to call it the biggest capitulation of the campaign.

Only 22 per cent of those polled believed Australia should wait for China and India to sign up to a post-2012 deal while 61 per cent thought Australia should ratify the Kyoto Protocol and 13 per cent opposed the move.

The survey also found Labor was the best major party to deal with climate change by 35 per cent to the Coalition's 15 per cent.

Thirty per cent thought the parties were the same in this area and 21 per cent didn't know who was better.

Among undecided voters, the margin was closer at Labor's 21 per cent to the coalition's 13 per cent.

"There is a clear thirst for leadership on climate change amongst voters, with a thirst mostly unsatisfied," institute chief executive John Connor said.

"It would appear that both parties were marked down over their squabble on Australia's role in global negotiations."

The poll, conducted by the Australian Research Group, surveyed nearly 900 voters in nine marginal seats in NSW, Queensland and South Australia from last Saturday to Monday.

Mr Howard's Sydney electorate of Bennelong was included.

AAP