US President Donald Trump has made a howler at a speech in Wisconsin by forgetting House Speaker Paul Ryan's name while giving a speech - a gaffe made even worse due to the speech being made in the 47-year-old's home town.

The former business mogul was in the process of making a joke about Mr Ryan's absence due to previous commitments with NATO - and it started well, with Mr Trump getting his name correct at first.

"My thanks go to Speaker Ryan, who's represented this city for nearly two decades in Congress," he said. "You know where he is? He's with NATO, and so he has a good excuse."

However it quickly went downhill when President Trump attempted to refer to the Republican by his first name - because instead of calling him Paul, he accidentally labelled him Ron.

"I said, 'Ron, you've got to get these countries to start paying their bills a little bit more'," he teased. "They're way, way behind, Ron."

While some have speculated that he had got him confused with former Republican Ron Paul, it is more likely that Mr Trump had mixed Mr Ryan's name up with that of Senator Ron Johnson, who was in attendance at the speech.

President Trump appeared to have realised his mistake shortly after, and in attempt to cover his gaffe smoothly, brought Senator Johnson back into the conversation by imploring him to follow Paul Ryan's lead by getting other countries to pay back their debts.

"I'm going to talk to you about that too, Ron," he said.

The latest gaffe is the latest in a string of mistakes made by Mr Trump's administration in recent times.

Last month Mr Trump referred to a man named Chuck as Ken moments after claiming "we don't make mistakes", while his press secretary Sean Spicer has found himself in hot water for referring to Australian Prime Minister Malcolm Turnbull as 'Trumble', and making the false claim that Hitler didn't use chemical weapons during the Holocaust.

Newshub.