PM Turnbull meets Russian President Vladimir Putin over Syria crisis at G20

Russian President Vladimir Putin has agreed with Malcolm Turnbull that a political solution is the key to Syria's long-term stability.

The prime minister met informally with the Russian leader on the sidelines of the G20 summit in the eastern Chinese city of Hangzhou yesterday.

The pair discussed the challenges of Syria and agreed a workable political solution was vital.

Mr Putin said it required a transition, not a revolution, and this would include elections some time in the future.

But the most immediate issue was to defeat all terrorist groups in the region, the Russian leader said.

Australia and Russia are seeking a counter-terrorism memorandum of understanding, which both leaders said they would work quickly to conclude.

Mr Turnbull also raised the issue of the downing of MH17 over Ukraine, saying Australia would continue to work towards bringing the culprits to justice.

Mr Putin acknowledged this was important for Australia.

Mr Turnbull earlier told reporters the need for a political solution in Syria was "greater than ever".

"The problem is that the various parties are well resourced. The Assad regime in particular of course has Russian support," he said.

"Bringing them together has proved to be very, very challenging."

However, Mr Turnbull said Australia was committed to the destruction of Islamic State in the field and would be "unrelenting" in this effort.

The prime minister last week announced new laws would ensure there are no legal hurdles to targeting IS members.