Cohen in payoff to Playmate for Trump ally

US President Donald Trump's personal lawyer arranged for a $US1.6 million payment to a Playboy Playmate to keep secret her sexual relationship with a top Republican fundraiser and ally of Trump, a person familiar with the matter says.

Michael Cohen, whose home and office were raided this week by FBI agents searching in part for information about pay-offs to women alleging sexual encounters with Trump, handled the matter on behalf of the fundraiser, Elliott Broidy, the person said.

The person, who spoke on condition of anonymity, was confirming a report by the Wall Street Journal.

In a statement on Friday, Broidy acknowledged that he had a relationship with a Playboy Playmate and offered to help her financially after she told him she was pregnant. The woman's name has not been made public and the source declined to disclose it.

"She alone decided that she did not want to continue with the pregnancy and I offered to help her financially during this difficult period. We have not spoken since that time," Broidy said in the statement.

Broidy said Cohen contacted him after being contacted by the woman's lawyer, Keith Davidson. Broidy said he retained Cohen because Cohen had a prior relationship with Davidson.

Cohen and Davidson did not immediate respond to requests for comment.

A source familiar with the situation said Republican National Committee chairwoman Ronna Romney McDaniel has accepted Broidy's resignation.