MPs and senators have returned to Canberra on Monday for a fortnight of parliament sittings set to be dominated by election speculation.

The latest Newspoll, published in The Australian on Monday, showed Labor and the Coalition tied at 50-50 in two-party preferred terms.

The Coalition’s primary vote has slumped three points to 43 per cent since January, the lowest level since Tony Abbott was ousted by Malcolm Turnbull in September.

Turnbull remains preferred prime minister with a 55-21 per cent lead over Labor leader Bill Shorten.

The prime minister’s satisfaction rating with voters remains in the positive (plus 10), but is significantly down on his plus 38 point high in November.

Turnbull tried to dampen election speculation, saying he was sticking by his timetable.

“I’m working on the assumption that the election will be held at the normal time, which is August, September, October,” the prime minister told reporters in Canberra.

Liberal frontbencher Simon Birmingham defended the government’s performance saying it was being “cautious and meticulous” with the task of economic reform.

“Australians know elections in Australia are hard fought battles,” he told Sky News.

“Polls go up and down.”

Labor senator Sam Dastyari says the gloss has come off the prime minister, whose personal rating soared in the weeks after ousting Abbott.

“The reality is the honeymoon is over for Malcolm Turnbull,” he told reporters in Canberra.

Liberal frontbencher Peter Dutton concedes the government has a lot of work to do.

“The prospect of Bill Shorten leading the country is now in play,” he said.

Coalition members meeting on Monday are understood to be discussing changes to the way senators are elected.

While Labor is divided on the issue, the government is eyeing off a deal with the Greens to simplify Senate voting in time for the next election.

Liberal Democrats senator David Leyonhjelm said changing the system to suit the government’s purposes and eliminate micro-parties is childish.

“It’s sort of like saying: `We’ve been playing in the sandpit all these years – now you’ve figured out how to build nice sandcastles I’m going to take all my toys and kick sand in your face’,” he told reporters in Canberra.

Labor fears the informal vote could dramatically increase.

The government already has two triggers for a double-dissolution election which could be held as late as July, but it could have a third if the Senate again rejects a bill to reinstate the building industry watchdog.

Much of the parliamentary week will deal with bills relating to last year’s budget savings.

Turnbull urged the Senate to pass legislation restoring the building and construction watchdog to avoid giving the government a third double-dissolution trigger.

AAP