The prime minister will have to navigate a series of tricky political issues working alongside an emboldened junior coalition partner led by a headline-grabbing populist.

Joyce argues the Nationals' leadership change increases the government's chances of being re-elected.

The high-profile MP's pitch to colleagues has long been that he can achieve greater media exposure and will more stridently stand up to the Liberals at the cabinet table than Michael McCormack.

The Nationals were already shaping for a fight on any increased climate ambition.

But the balance between foreign policy and domestic politics just became more delicate.

Morrison is in a tough bind with major allies demanding Australia do more ahead of the UN's climate conference at Glasgow in November.

There could be serious economic consequences if the European Union and others forge ahead with plans for punitive tariffs on imports from laggard nations.

Joyce-led Nationals are almost guaranteed to thwart any chance of the government adopting a 2050 target to reach net zero carbon emissions.

Critics say Morrison places domestic gain on a higher plane than foreign policy.

With an election due between August and May it's hard to see the prime minister risking a messy stoush with the Nationals on energy.

It's a minefield policy area that has detonated multiple political leaders' careers.

Female Nationals MPs have also publicly worried Joyce's return will further damage the government's standing with women.

It's an even more salient concern with the government under pressure after months of damaging revelations about the culture at Parliament House.

Joyce's economic tendencies will also be fascinating after he declared the government's pandemic-fuelled spend-a-thon must end.

On top of that, he wants a Tamil asylum-seeker family in detention returned to their regional Queensland home.

It's hard to accept suggestions McCormack's performance as acting prime minister was behind the spill.

The Wagga Wagga MP achieved fabled media cut-through with an incendiary parliamentary blast at animal activists.

The Nationals clinched a deal for an agriculture visa the government has resisted for years, while Keith Pitt - who McCormack promoted to cabinet - muscled up to the Liberals on emissions.

Not for the first time, ambition and personality triumphed.

Now to the victors go the spoils.

Bridget McKenzie is poised for a return to cabinet less than 18 months after being forced to quit over undeclared gun club memberships during the sports rorts saga.

Little-known junior minister Andrew Gee would be hopeful of a more significant portfolio after rumours he was a crucial Joyce backer who switched sides in recent days.

Matt Canavan has been Joyce's biggest public agitator but insists he doesn't want to return to the front bench.

Veterans' Affairs Minister Darren Chester is almost certain to be booted out of cabinet by Joyce for a second time.

Morrison's management of old and new faces looms as a major test for a man supporters hail as a political genius.

Australian Associated Press