US federal prosecutors have reportedly granted immunity to David Pecker, CEO of company that publishes the National Enquirer, and his top lieutenant, Australian journalist, Dylan Howard, in the investigation into Donald Trump’s former lawyer, Michael Cohen.

Vanity Fair reported that Mr Pecker’s immunity deal extended to the former Channel 7 journalist, Mr Howard, chief content officer of the National Enquirer’s parent company, American Media Inc.

The Wall Street Journal reported that Mr Pecker met with prosecutors to describe the alleged involvement of Mr Cohen and Mr Trump in financial deals to two women ahead of the 2016 US election.

The New York Times reported in June that Mr Howard had allegedly been subpoaned by federal prosecutors over the claims.

The prosecutors had already reportedly asked for communications between Mr Cohen, Mr Pecker, and Mr Howard.

That request was said to be part of a search warrant they secured for Mr Cohen’s home, office, hotel room and mobile phones in April.

Court papers showed how Mr Pecker, longtime friend of the president and Mr Cohen, and head of the Enquirer’s parent company, offered to help Mr Trump stave off negative stories during the 2016 campaign.

Playboy Playmate Karen McDougal reached a deal to be paid $US150,000 ($A204,000) for her story about an alleged affair in 2006 and 2007, prosecutors said, for a story that never ran.

It is a tabloid strategy known as “catch and kill,” or paying for exclusive rights to someone’s story with no intention of publishing it in order to keep it out of the news altogether.

Daniels, whose real name is Stephanie Clifford, negotiated a $US130,000 ($A176,000) payment through Mr Cohen for her story — and both were successfully buried until after the campaign.

Mr Howard has had his own issues over the years.

In 2008, he was sacked from Channel 7 over a stolen AFL medical files investigation.

Channel 7 caused a storm of player boycott threats when it broadcast confidential details of two unnamed players’ drug use and subsequent counselling in September 2007.

Mr Howard was cleared by police.

He was also alleged of have tried to silence some of Harvey Weinstein’s accusers.

In 2017, it was reported that Mr Howard was the subject of a 2012 internal investigation after he was accused of sexual harassment in the workplace when former colleagues told the Associated Press that he described his sexual partners in the newsroom, discussed female employees’ sex lives and forced women to watch or listen to pornographic material.

Howard quit the company but was rehired in 2013 with a promotion that landed him in the company’s main office in New York, where he is still based.

The relationship between Mr Trump and the National Enquirer has been cozy for decades. Former National Enquirer employees who spoke to the Associated Press said that negative stories about Mr Trump were dead-on-arrival dating back to when he starred on the reality show The Apprentice.

Earlier this week, the plea deal reached by Mr Cohen has exposed a relationship between the president and the publicationthat goes well beyond screaming headlines.

The accusations threaten the tabloid’s parent company, American Media Inc, both legally and in the court of public opinion.

The National Enquirer has yet to comment.