Canadian Prime Minister Justin Trudeau announced Monday he is resigning after nearly a decade in office following mounting calls for him to step down and “internal battles” within his lefty party.

The 53-year-old, who has been in power since 2015, said he plans to stay in his post until his ruling Liberal Party chooses a replacement in the wake of his stunning fall from grace.

“I am a fighter, and I am not someone who backs away from a fight, particularly when a fight is as important as this,” Trudeau said at a news conference outside his home at Rideau Cottage in Ottawa.

“But I have always been driven by my love for Canada, by my desire to serve Canadians and by what is in the best interests of Canadians — and Canadians deserve a real choice in the next election.

“It has become obvious to me, with the internal battles, that I cannot be the one to carry the liberal standard into the next election,” he added.

The announcement comes after an embattled Trudeau was hit with a barrage of calls to quit in recent weeks in the wake of a slew of alarming polls indicating dwindling support.

Grim polling has shown that his party would lose badly to the opposing Conservative Party, led by rival Pierre Poilevre, with him still at the helm for the next election, which has to be held by late October.

Canada’s Parliament, which had been due to resume Jan. 27, will now be suspended until March 24 — allowing the Liberal Party to hold a “robust, nationwide competitive” leadership race to replace him, Trudeau said.

He added that he had already asked the president of his party to begin the process of selecting a new leader.

“It’s time for a reset,” Trudeau said, adding that Parliament had been “seized by obstruction, filibustering and a total lack of productivity” in the past few months.

“It’s time for the temperature to come down, for the people to have a fresh start in Parliament, to be able to navigate through these complex times,” the PM said.

Trudeau has seen his popularity plummet in recent years over a range of issues — including spending and the soaring cost of food and housing.

Calls for him to step down also gained momentum after his then-finance minister, Chrystia Freeland, abruptly quit last month.

Her shocking resignation came after Trudeau tried to demote her when she pushed back against his proposals for more spending.

Freeland penned a scathing letter accusing Trudeau of “political gimmicks” rather than focusing on what was best for Canada’s economy.

The political upheaval comes, too, as a Donald Trump presidency — and the threat of 25% US tariffs on all Canadian products — loom large.

Trump, who has consistently needled the Canadian PM since winning the US election, has threatened to impose the tariffs on all Canadian products if Canada doesn’t stem what the president-elect calls a flow of migrants and drugs across the border.

Trudeau, the son of former Canadian PM Pierre Trudeau, took over as the lefty leader back in 2013 when the party was in deep trouble and was reduced to third place in the House of Commons for the first time in history.

He then propelled the Liberals to power in 2015 with the promise of “sunny ways” and a progressive agenda pushing women’s rights and a fight against climate change.

Trudeau went on to win re-election twice — becoming one of Canada’s longest-serving prime ministers.

In his resignation announcement, Trudeau ripped Poilievre, arguing the conservative leader wasn’t the right vision for Canadians.

“We need an ambitious, optimistic view of the future, and Pierre Poilievre is not offering that,” he said.

Poilievre rose to prominence in early 2022 when he backed truck drivers who took over the center of Ottawa as part of a protest against COVID-19 vaccine mandates.

With Post wires