American evangelist Franklin Graham says the political Left are "attacking" Donald Trump because they are "scared to death" that he will make a return to office.

Reports that the former US President would be arrested on Tuesday did not materialise but the Manhattan District Attorney is still investigating his involvement in an alleged hush money payment to porn star Stormy Daniels in 2016.

Graham, the son of the late Billy Graham and President of Samaritan's Purse, was a staunch supporter of Trump during his presidency and came out in support of him again in a Facebook post this week.

He said that Trump was facing an "onslaught" by the media and political Left to stop him returning to the White House.

Graham asked his followers to pray.

"We need to pray for our country and where it's headed," he wrote.

"The Left in Washington and across the country just can't get their fill of attacking Donald Trump. They are so paranoid of him. The onslaught against him is continual."

Franklin went on to say that it would be a "huge mistake" to arrest Trump.

"There's no question, the media and the left manipulated the last election, and they are scared to death of Donald Trump's possible return," he said.

"Night after night, the media runs negative stories about former President Trump. Now they're talking about the possibility of arresting him in the hopes that this would prevent him from running for president again — this would be a huge mistake.

"The charges against him are definitely politically motivated."