Rival media outlets have become unlikely allies in boycotting US President Donald Trump after he controversially banned reporters from the White House.

Trump banned CNN, MS NOW and Politico employees from the White House on Friday, calling the outlets “fake news” and claiming that access is “a privilege, not a right”.

WATCH THE VIDEO ABOVE: US media outlets sue Trump over White House ban

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Reporters from the networks had their entry badges denied on Saturday, with all three outlets filing a joint lawsuit against the Trump administration on Monday.

“This morning, we notified the government that we are filing a lawsuit today to protect our First Amendment rights and defend the principle that the government does not decide what the press reports or publishes,” they said in a joint statement.

“Left unchallenged, this threatens press freedom and the public’s right to independent journalism free from government interference.”

The lawsuit alleges Trump’s ban is in breach of the US constitution’s first amendment; the right to free speech.

Multiple media outlets are boycotting US President Donald Trump after he banned several outlets, including CNN, from the White House. Credit: AP

“(The constitution) does not allow a president or any other government official to deprive the press of their First Amendment rights and liberty and property interests with no notice or process based solely on his dislike of the content of their reporting,” the lawsuit alleges.

Former White House Spokesperson Pete Seat told Sunrise the outlets “should win” the legal battle as the “White House cannot refuse access based on coverage”.

“If they want to make the case that it’s based on security or capacity of the White House briefing room, the Oval Office, other spaces within the White House, that’s another thing,” Seat said.

“But to say that it’s based on their coverage will likely not stand up to constitutional or legal scrutiny.”

It’s the latest legal test of free speech under Trump, who has routinely attacked the press throughout both of his presidential terms.

Unlikely allies in Trump boycott

The three banned outlets are part of a press pool which follows and reports on the president, and also includes ABC, CBS, Fox News and NBC.

Despite being rivals in the media landscape, the ban led to all of the news outlets becoming unlikely allies to boycott coverage of Trump.

“Effective today, there would be no network pool coverage of the president’s events,” Fox News’s Washington bureau chief and the White House TV pool chair Bryan Boughton write in an email to subscribers.

“This follows the White House’s position preventing CNN from fulfilling its assigned pool duties.

“There will be no replacement pool put in place.”

Trump’s latest attack on the press has prompted banned media outlets to sue his administration over an alleged breach of free speech. Credit: AP

Journalists were spotted reporting from an intersection near the White House on Monday following the boycott, which constricts Trump’s ability to reach the American public through the news.

CNN’s chief White House correspondent, Kaitlan Collins, explained on air what this meant: “When the president does anything today, there will be no TV camera with the president that is broadcasting and sharing this footage.”

It’s already meant that viewers of the pool feed could not hear Trump’s speech during the opening of the new White House helipad later that day.

Other news outlets including the Washington Post, New York Times and the Associated Press have also stood in support of the boycott by refusing to publish images taken by a separate photography pool.

- With AP