The US Republican Party is to open its convention and officially nominate former president Donald Trump as its candidate for the presidential election in November.

The four-day Republican National Convention will start in Milwaukee in the Midwestern state of Wisconsin on Monday afternoon.

The meeting opens two days after Trump was shot and wounded on his right ear during a speech at a rally in the eastern state of Pennsylvania on Saturday.

He arrived in Milwaukee on Sunday as planned to attend the convention.

In a social media post, Trump said he "just decided that I cannot allow a 'shooter,' or potential assassin, to force change to scheduling, or anything else."

He also told a US media outlet that he rewrote his acceptance speech in light of the shooting and indicated that the convention will be an opportunity to bring the country together.

The former president is likely to show that he will not give in, and hopes to gain momentum for the November election.