Prime Minister Malcolm Turnbull has signalled he may be open to fixed four-year terms for federal parliament after Opposition Leader Bill Shorten renewed his call for an overhaul of Australia's electoral system.

Key points: Opposition Leader Bill Shorten calls for fixed four-year parliamentary terms

Opposition Leader Bill Shorten calls for fixed four-year parliamentary terms Malcolm Turnbull called Mr Shorten to discuss push; Shorten offered to meet with PM

Malcolm Turnbull called Mr Shorten to discuss push; Shorten offered to meet with PM The change could only be introduced through a referendum

At the moment federal parliaments only run for up to three years — and prime ministers have broad powers to call elections when they please.

But on Sunday morning, Mr Shorten told the ABC's Insiders program the current system was stifling reform, and federal parliaments should run for a fixed term of four years instead.

"The federal political system seems out of whack in that everything is so short-term. The average life of a federal government is two-and-a-half years — not even three years," Mr Shorten said.

"Governments can be more daring and determined if they're not constantly thinking about the next election, if prime ministers of the day don't have the tempting trigger to pull that if they have an improvement in their short-term position they'll race to the polls."

Mr Turnbull rang Mr Shorten not long after that interview went to air and the two men talked about the Opposition Leader's intervention.

They agreed to discuss the issue when they next meet — but it's not clear if the Prime Minister specifically endorsed Mr Shorten's plan.

Mr Shorten has previously backed four-year terms, but said it was not a priority for the ALP.

His intervention signals Labor might be willing to expend political capital on the issue — and Mr Turnbull's response indicates he may be interested in change as well.

Most states have now embraced fixed terms, and several business groups have backed the idea, saying it would help create a more stable political environment.

Shorten says parties should agree to take issue to voters

Earlier this year Liberal MP David Coleman introduced a draft bill for four-year terms, arguing it would make it easier for governments to implement complex long-term policies.

Last year, Finance Minister Mathias Cormann also backed the concept of fixed four-year terms, but indicated it was not a pressing issue for the Turnbull Government.

The change could only be introduced through a referendum — and Mr Shorten said both major parties should agree to take the issue to voters after the next election.

"If Labor just said we wanted four-year terms, it would fail," he said.

"Now, I'm saying that I would be prepared ... to say that before the next election.

"Why couldn't the government of the day — Mr Turnbull or whoever is in charge — and myself agree that whoever wins the next election, that together, we would have an agreed change to the constitution which we would put to the Australian people of four-year terms."

Four-year parliamentary terms were proposed in a 1988 referendum but it was defeated after less than one in three voters backed the change.