Republican presidential candidate Donald Trump is confident he will win his party's nomination in the first round of balloting at its convention in Cleveland, Ohio in July, a new memo by his campaign advisors revealed. The memo, which claims Trump is the "prohibitive favourite," projects he will accumulate over 1,400 delegates to secure the nomination.

According to The Washington Post, the memo was distributed late on 19 April following the real estate mogul's big win in New York. The memo described his win as "YUGE" and reportedly encouraged the candidate's supporters to call out the so-called "rigged" process of delegate selection for the Republican National Convention.

The memo also touched on Trump's rival, Texas Senator Ted Cruz, who is behind Trump in delegate numbers. "The Cruz spin machine produces more lies than anything else," it said. "Our projections call for us to accumulate over 1,400 delegates and thus a first ballot nomination win in Cleveland."

Following his victory in New York, Trump leads with 845 delegates followed by Cruz with 559 and Ohio Governor John Kasich with 147. Candidates require 1,237 delegates to win the nomination.

Despite Trump's assertions that he will win enough delegates, his rivals claim that no one candidate will win the nomination outright. According to CNN, Cruz, who faced a crushing defeat in New York, appears convinced that the Republican field would have to deal with a contested convention in July.

"We are headed to a contested convention. At this point, nobody is getting 1,237," Cruz told Philadelphia radio host Chris Stigmal on 20 April. "Donald is going to talk all the time about other folks not getting to 1,237. He's not getting there, either." He repeated that belief to CNN and said: "The reason Donald's so scared is the last three weeks – and in particular, the win in Wisconsin –put the nail in the coffin and made clear Donald doesn't get to 1,237."

Kasich agrees that none of the candidates will reach the necessary delegate counts. "Here's what's happening, nobody is going to get enough delegates," Kasich told a crowd in Annapolis, Maryland. "I mean the Trump organisation is complaining all the time about this and that and you know why? Because they know they're not going to get enough votes."

The three remaining GOP players will face off in five states on 26 April. The races in Connecticut, Delaware, Maryland, Pennsylvania and Rhode Island will be the last before May.