With Mr Turnbull and other Liberals riding high over Thursday's historic amendment to the Marriage Act, progressives inside the party believe the lesson is that Australians are not as conservative as claimed.

Some are confident the successful conclusion of the issue before the 2018 parliamentary year has cemented Mr Turnbull's leadership, weakened the right, and could yet prove a "turning point" for the Coalition in the polls.

Ministers told Fairfax Media the government had finished the year in better shape than expected, but the leadership group was "well aware" more needed to be done in 2018.

Attorney-General George Brandis told Fairfax Media the same-sex marriage result was "a practical demonstration of what the Prime Minister said a few months ago in his Menzies Lecture in London - that Australians prefer their governments to be mainstream, to govern from the centre."

Senator Dean Smith, the Liberal backbencher whose private members' bill passed unamended on Thursday evening, encouraged the government to draw closer to the middle.

"For the Liberal Party to be successful in government it needs to constantly win and appeal to the centre," he told Fairfax Media. "That is the political lesson out of the postal survey and one that has to be top of mind when we come back in 2018.

"These are opportunities that the government must embrace. Taking the euphoria and the joy and the success of this issue and using it to recast the government into the new year, to allow the government to perhaps revisit some issues that have proven difficult in the past."

Senator Smith said the same-sex marriage survey opened a broader window to the Australian mainstream.

"What we've seen in recent years is some Liberals wanting to argue for and represent a narrower base which is at the fringe of the spectrum," he said.

"We need to be very, very careful that we don't get unnecessarily distracted by issues that might play to the narrow base of the Liberal Party but do nothing to meet those needs of Australians in the centre-right. Elections are not won chasing the fringe."

One minister said it was "not rocket science" that the best approach for the government was pragmatism over ideology.

However, a strong Turnbull backer cautioned there was still a "realistic concern about losing votes to the right" - a reference to the threat from Pauline Hanson's One Nation.

"The Queensland election shows we do have a problem and it's akin to Labor's problem with the Greens".

Andrew Bragg, a former acting director of the Liberal Party and the director of Libs and Nats for Yes campaign, warned same-sex marriage was not a good proxy for other issues because it was not strictly a "progressive" cause.

"It's not a green light to jump into the centre, it's not a green light to jump to the left," he told Fairfax Media. "It's an issue that's torn the party apart, but it's not a good proxy.

"The Liberal Party's base really needs to be unified in pursuit of policies it unanimously supports. That necessitates ambitious policy on economic and security issues, but predominantly economic issues."

Mr Turnbull on Friday declared the economy will be the government's chief focus in 2018 after the passage of same-sex marriage cleared away an issue that has dogged the Coalition for most of the year.

Asked what the big theme for 2018 would be, Mr Turnbull said: "It is more money in the pockets of hardworking Australian families and business. It's getting on with delivering the national energy guarantee. Getting on with our business tax cuts which are already delivering nearly 1000 jobs a day - 85 per cent of them full-time, I might say - over the last year," Mr Turnbull told ABC Radio.

Sir Peter Cosgrove gave the laws royal assent on Friday morning when he was visited by Mr Turnbull and Senator Brandis.

Mr Turnbull described the postal survey as a game-changer for the issue and criticised Labor for not progressing the matter when in office.