However, a spokesman for the Prime Minister said today that raising the GST rate was not on the government's agenda.

"The Prime Minister said before the election that over his dead body would there be an increase in the level of the GST.  That commitment still stands and will not be changing in the future," a spokesman said.

Mr Rudd said yesterday that the time had come for a "root and branch" review of taxation, but that it was too soon for him to commit to holding a review within two years.

Before the election last year, Labor promised to cut the number of tax rates from four to three within six years.

Victorian Premier John Brumby has said a tax review is timely as Australia calculates the cost of addressing climate change.

"If there's a potential carbon price, there's an opportunity to look at the existing taxes, particularly, I think, some of the taxes on imports," he said.

He said the balance between federal and state taxes could also do with a rethink.

"The states do the bulk of the heavy lifting work in terms of delivering things like the ambulance services ... things like hospital services, education, schools, community safety," he said, "... but it's the Commonwealth that collects the bulk of the taxes."

Streamlining the duplication and inefficiencies in the federalist system was another common theme from the 2020 summit.