Donald Trump has reportedly won enough delegates to secure the Republican presidential nomination, securing 1,238 of 1,237 needed to win.

Several unbound delegates have reportedly told AP they will be supporting Trump at the Republican Convention, meaning he has not only achieved the necessary number of delegates to win the nomination, but with 303 delegates up for grabs at the 7 June primaries, he is expected to greatly exceed the required number.

Despite being the presumptive presidential nominee since his closest rival Ted Cruz dropped out of the race in May, Trump's failure to secure the necessary delegates ahead of July could have made for a messy convention – something the GOP has been keen to avoid.

Oklahoma Republican chairwoman Pam Pollard, who is one of the unbound delegates whose support has bumped Trump up to his current 1,238 delegates, told AP: "I think he has touched a part of our electorate that doesn't like where our country is. I have no problem supporting Mr. Trump."

Neither Trump nor his campaign team have yet responded to the news that his numbers have been bumped up by unbound delegates – possibly waiting for official figures from the upcoming primaries to presume his win.

However, several of the delegates who spoke to AP suggested they were voting out of obligation and stated if there had been a second round of voting, Trump would not have their backing.

The businessman, whose run at the nomination was initially viewed as a wildcard entry, is expected to run against Democrat frontrunner Hillary Clinton, who is polling ahead of her rival Bernie Sanders.