Republican presidential aspirant Donald Trump has criticised US President Barack Obama for entering into a "dumb" nuclear deal with Iran.

Trump said in a radio interview that the Obama administration failed to negotiate with Iran from a position of strength.

The controversial business tycoon said the US government should have exerted more pressure on Iran to totally abandon its plan to build nuclear weapons by imposing more sanctions on them.

"I guarantee you if I was involved, they would have let 'em out... They should have doubled up the sanctions, and negotiated from strength," Trump said in an interview last Sunday in New York with WABC Radio.

"They could have sanctioned the hell out of 'em. There would be no war – they would have come to the table, we would have won everything," he added.

Iran earlier agreed to limit its nuclear activities, in return for an end to international sanctions against it. The United Nations Security Council is scheduled to vote on the resolution endorsing the Iran nuclear deal next week.

Trump, however, described the Iran nuclear deal as "terrible."

"[It's] just insulting. It's such a bad deal... One of the really dumb deals I've ever seen," he said.

The Republican presidential aspirant further said the US government should have pressured Iran into releasing four Americans imprisoned in Tehran.

"How do you complicate the negotiations by asking for four people that should not be in jail? It is so disgraceful the way this was handled, and it shouldn't have taken this time. They should have doubled up the sanctions. And I mean double and triple up the sanctions, and had them come home," Trump said.

"They don't have the cards – we have the cards," he added.

Trump further said that Iran's chief negotiator, Foreign Minister Mohammad Javad Zarif, outwitted American officials.

"This guy is too smart, and he's too sharp, and he's too cunning for [Secretary of State John] Kerry, and our bunch of negotiators," Trump said.