The Green Party will have to fight to hold on to its identity if it enters into a coalition with Labour at next year's election, an Australian Greens politician says.

Speaking at the Green Party conference in Christchurch, Victorian senator Richard Di Natale said Greens would have to be very clear about what policies and principles they would not compromise on.

His party had a confidence-and-supply agreement with Julia Gillard's Labour Party, but that had now been disbanded and the parties were attacking each other in campaigning.

Senator Di Natale said Australia's Greens had been highly influential in some of the Government's cornerstone policies, such as putting a price on pollution, a new $10 billion investment in renewable energy, and free dental care for children.


However, it was dismayed at Labour's reluctance to tax industry during the mining boom, which it felt could have channelled money into public health and education.

"The key issue is knowing when not to compromise," Dr Di Natale said.

He warned that it was easy for minority parties to be diluted or belittled when part of government.

"Maintaining your identity when there is a perception that you are part of the government is a huge challenge.

"You are often lumbered with the mistakes of the majority partner and on those things were achievements were made it can sometimes be difficult to have your role recognised."