Former Republican presidential nominee Mitt Romney predicted Monday that Donald Trump will become the GOP nominee if both of his opponents remain in the race until the convention this July.

"I think that Mr. Cruz and Mr. Kasich divide the vote, and that makes it easier for Mr. Trump to win the winner-take-all congressional districts and the winner-take-all states and get the delegates he needs to either hit the 1,237 or get close enough to sway the uncommitted delegates on the first ballot," Romney said during a podcast with CNN's David Gregory, which is set to be released in full on Friday.

Should Texas Sen. Ted Cruz or Ohio Gov. John Kasich exit the race before the Republican National Convention, Romney said it is unlikely that Trump would be able to collect the 1,237 delegates needed to secure the nomination.

Despite revealing before the Utah caucuses last month that he planned to vote for Cruz, Romney would not disclose which of Trump's opponents he believes should end their White House bid after Tuesday's primary in New York.

Cruz leads Kasich by more than 400 delegates at this point in the race, and the Texas senator has won a substantial number of delegates who would support him over Trump on a second ballot if Republicans face a contested convention. But the Texas senator remains about 200 delegates behind Trump in the overall count.

Romney also dismissed the Trump campaign's recent claims that delegate selection rules were changed to make the billionaire's path to the nomination more difficult.

"Well, actually at this stage of course the rules are the rules, and the party put them out there well over a year ago," he said. "And they're very similar to the rules that existed at the time when I was running four years ago."

The former Massachusetts governor continued, "By the way, there's probably nothing wrong with making it difficult. After all, these rules are a lot simpler than the rules of foreign affairs for instance or the rules of our economy.

"And if you want to be president, you're going to have to deal with rules far more complicated than Republican delegate rules," he said.