John McCain has, in death, exacted his final revenge on Republican foe Donald Trump by not inviting the sitting president to his funeral.

Mr McCain, the 2008 US presidential contender and unrelenting critic of Mr Trump, died of brain cancer on Sunday.

The war veteran and long-serving Senator will receive the rare honour of lying in state in Washington’s Capitol Rotunda before a full dress funeral service at the Washington National Cathedral.

Former presidents Barack Obama, who contested the 2008 race against Mr McCain, and George W Bush have been invited to deliver eulogies at the funeral, according to US media.

Vice President Mike Pence was to attend, but not Mr Trump, who clashed repeatedly with Mr McCain, the New York Times quoted senior Republicans as saying.

The 81-year-old war hero and veteran politician passed away at his Arizona home 13 months after revealing he was suffering from an incurable and highly invasive brain cancer.

The end came quickly for the man who endured half a decade in a North Vietnamese prison. It was only on Friday that a spokesman confirmed the fiercely independent Republican had stopped treatment.

Australia’s new Prime Minister Scott Morrison was quick to express his condolences, hailing Mr McCain for “strengthening the alliance between our two nations”.

“He was a man of great courage and conviction. Our thoughts and prayers go out to his wife, Cindy, and all the McCain family during this time,” Mr Morrison tweeted on Sunday.

Senator John McCain was a true friend of Australia who was committed to strengthening the alliance between our two nations. He was a man of great courage and conviction. Our thoughts and prayers go out to his wife, Cindy, and all the McCain family during this time.

— Scott Morrison (@ScoMo30) August 26, 2018

Australia’s Ambassador to the United States Joe Hockey also paid his respects.

“How terribly sad to hear that Senator John McCain has passed away,” he wrote on Twitter.

“People who love justice, democracy, freedom and courage will mourn this loss of an American legend.”

Mr McCain was known to the end as a pugnacious maverick, last month offering blistering criticism of Mr Trump’s failure to stand up to Russian President Vladimir Putin.

“With the Senator when he passed were his wife Cindy and their family. At his death, he had served the United States of America faithfully for 60 years,” his office said in a statement.

Mr McCain was diagnosed in July 2017 and tried valiantly to maintain his involvement in politics as the cancer spread.

A fighter to the end, McCain reported to Washington for vital votes even as cancer ravaged his body. Photo: EPA

The retired Navy fighter pilot, who was shot down over North Vietnam in 1967 and held as a prisoner of war for more than five years, entered Congress in 1983 from Arizona and moved to the Senate four years later.

During his time in captivity, including two years in solitary confinement, Mr McCain was frequently beaten and tortured, leaving him permanently disabled. In the Senate, he was a critic of harsh interrogation techniques such as “waterboarding” or simulated drowning of terrorism suspects.

Days after undergoing brain surgery in Arizona, with open stitches above his left brow, Mr McCain appeared on the Senate floor in late July 2017, delivering a speech against partisanship and eventually casting the deciding vote against a major health care measure supported by Mr Trump.

The hawkish chairman of the Senate Armed Services committee was a top Republican voice on defence and foreign policy and mounted losing presidential campaigns in 2000 and 2008.

He gave then-Texas governor George W Bush a scare in 2000 by decisively winning the first of the Republican state nominating contests. Later he fared poorly in the ‘Super Tuesday’ nominating races and eventually conceded to Mr Bush after a bitter campaign.

After winning the Republican presidential nomination in 2008, Mr McCain lost the popular vote to Mr Obama, 53 per cent to 46 per cent.

In Congress, he was a pro-business conservative, free-market advocate and abortion foe but he voted against the Republican majority on several high-profile bills. After being cleared in the 1980s in the ‘Keating Five’ campaign donation scandal, he made election campaign finance reform a signature concern.

Mr McCain was a leading Republican critic of the Trump presidency.

Mr McCain campaigning with Mitt Romney in 2012 in Florida. He endorsed Mr Romney’s Republican bid for the presidency that year. Photo: Getty

After he criticised Mr Trump’s harsh campaign rhetoric on illegal immigration, Mr Trump disparaged Mr McCain’s military service by saying he preferred “people who weren’t captured”.

Mr McCain, out of party loyalty, later endorsed Mr Trump once he had secured the Republican nomination. But he withdrew his support in October 2016 after a tape emerged in which Mr Trump boasted of grabbing women by the genitals.

Last month, after Mr Trump failed to publicly confront Mr Putin about election meddling, Mr McCain called the Helsinki summit “one of the most disgraceful performances by an American president in memory”.

Nevertheless, the usually caustic Mr Trump managed a restrained tweet when news of his political foe’s death broke, sending his “deepest sympathies and respect” to the McCain family.

South Carolina Senator Lindsey Graham, a fellow military officer and Republican, tweeted that Mr McCain was “one of my dearest friends and mentor”.

Mr McCain, bottom right, in 1965 with his Navy squadron. While in the Navy, he was cocky and combative and resisted discipline. Photo: National Archives

“America and Freedom have lost one of her greatest champions,” the Republican Graham wrote.

Democratic National Committee chairman Tom Perez said that Mr McCain “always will be an American hero”.

“John McCain devoted his life to serving his country,” Perez tweeted.
Paul Ryan, Republican speaker of the House of Representatives, said on Friday that McCain “personifies service to our country”.

Mr McCain was always a maverick. He was an unruly and even combative student at his Washington-area boarding school.

As the son and grandson of four-star Navy admirals, Mr McCain followed in their footsteps by attending the US Naval Academy, but rebelled against regulations and graduated near the bottom of his class.

In 2017, doctors found an aggressive brain tumour during surgery in Arizona to remove a blood clot behind McCain’s left eye.

More than 30 people have been honoured by lying in state in the Capitol Rotunda since 1852, a gesture reserved for the country’s “most eminent citizens”.

-with AAP