Donald Trump will get a hero's welcome on Thursday as he accepts the Republican Party's nomination to run for US president in a speech capping a convention dominated by the recent attempt on his life.

The 78-year-old will address the Republican National Convention in Milwaukee, Wisconsin hoping to build momentum toward victory over President Joe Biden in the November election and a second term in the White House.

Supporters have been lining up all week to applaud the former president for his bravery since Saturday's assassination bid by a gunman at a Pennsylvania rally.

As some of his loyalists blamed Democrats' rhetoric for the attack, Trump said he had torn up a more aggressive version of his keynote address in favour of one to "unite our country."

"I'm just grateful we're going to hear from him. It's a miracle that his life was spared, and I really believe it was God's hand," said Teena Horlacher, a 50-year-old convention delegate from Utah.

"I'd love for him to talk about Saturday, what his feelings were."

Trump has a 90-minute speaking slot, from 9:00 to 10:30 pm (0100 to 0230 GMT on Friday), according to a source familiar with the schedule.

Also set to address the convention are the world-famous retired professional wrestler Hulk Hogan, and longtime friend Dana White who is chief executive of the Ultimate Fighting Championship.

Trump has attended multiple UFC bouts as he seeks to cultivate his image as an alpha-male stereotype and lock in younger male votes.

The schedule notably shows no speaking slot for former first lady Melania Trump, a clear break from tradition at modern-era US nominating conventions, where spouses have almost always taken the stage in bids to personalise the candidates.

Trump has seen his poll lead expand since Biden's dismal debate performance last month threw his party into chaos.

The Republican campaign has even been talking up Trump's chances in Democratic strongholds like Minnesota and Virginia, potentially forcing Biden funds and manpower away from defending his "blue wall" in Michigan, Pennsylvania and Wisconsin.

Trump's keynote address on Thursday will be followed on television and online by millions, closing the convention by promising what his team calls "a new golden age for America."

It brings down the curtain on four days of speeches from elected officials, entertainers, industry figures and everyday Americans who mixed with some 50,000 Republicans attending the event.

The gathering opened on Monday with a vote to confirm Trump as the party's nominee after he won almost every state's primary contest.

It has been the first convention over which Trump has had total control, after a 2016 edition hampered by party divisions and a second appearance in 2020 reined in by the Covid-19 pandemic.

The schedule was designed around his image, with themes for each day playing on his "Make America Great Again" rallying cry.

Trump set the tone when he walked slowly into the Fiserv Forum arena on the opening day – looking emotional and with a bandaged ear, just two days after the shooting.

The week also saw Trump name right-wing Senator JD Vance as his running mate.

The 39-year-old author of "Hillbilly Elegy," a best-selling memoir about growing up poor in working-class America, is a one-time critic who has become one of Trump's most staunch backers.

Trump himself was a diminished figure after his 2020 election loss and a subsequent riot at the US Capitol by his supporters, but he has spent much of the last four years reshaping Republican politics.

Installing close allies, including his daughter-in-law Lara Trump on the Republican National Committee, the mercurial tycoon has effectively crushed dissent within the party.

Trump is increasingly confident of victory – despite multiple legal problems and two impeachments clouding his first term – as Biden is reeling from weak polls and concerns over his health.

At 81, Biden has been facing growing calls from his own side to quit the race, and he suffered another blow on Wednesday when he was diagnosed with Covid-19.

"There's a clearly stark contrast between the strength of President Trump and the weakness of President Biden," said Mississippi delegate Clifton Carroll.

"And I think he'll expand on that, and really send a message that the entire United States of America can get behind whether they're Republican, Democrat or Independent." (AFP)