Excerpts of US President Donald Trump's tax returns have been leaked to the media.

The form reveals Trump received an income of more than $150 million in 2005 paid $5.3 million in regular federal income tax, and $31 million in "alternative minimum tax" (AMT).

Trump has previously vowed to stamp out the AMT, which was implemented almost 50 years ago as a measure to assure the rich don't avoid paying their fair share of tax.

The published pages from his 2005 tax return revealed the overwhelming amount of tax he paid was accounted for by the AMT.

Source: MSNBC

Comment: Trump tax return is a total nothingburger

White House says Trump's tax return was 'illegally published,' but Maddow is probably in the clear

It was revealed the President's personal tax details would be published on Wednesday morning when MSNBC TV host Rachel Maddow sent the internet into an excited panic when she tweeted she would reveal the long awaited documents on her 9pm (US eastern time) show.

Beginning her program, the presenter said: "It ought to give you pause that his explanation have never made any factual sense."

She argued interest in the details of the documents was not a partisan argument.

"There are definitely personality-driven and petty reasons to be interested in the President's tax returns ... but whether it's for small reasons or big reasons, there has been unrelenting demand for him to release his tax returns," she said.

More than a million Americans have signed a petition urging the President to go public with the details.

After a very long preamble, Maddow revealed the network had obtained a two-page sample of the President's 2005 tax return.

The form, which had been delivered by an anonymous source to the inbox of Pulitzer Prize winning journalist David Cay Johnston was the federal income tax form used to report an individual's gross income.

It's been published on his website DCReport.org.

Speaking on MSNBC, Johnston said he had received the pages in the mail, and said it was possible the lead could have come from Trump himself.

Speculation has begun online as to where the leak originated. There has been particular interest in one marking on the second page of the forms - a stamp saying "Client Copy".

Some are suggesting the marking may indicate the document would have had to be in possession of Mr Trump's camp at some stage, rather than being leaked by the IRS.

Speculation over who leaked Donald Trump's tax return surrounds the 'Client Copy' stamp. Photo / MSNBC/Screengrab
Speculation over who leaked Donald Trump's tax return surrounds the 'Client Copy' stamp. Photo / MSNBC/Screengrab

Prior to the broadcast, the White House released an explosive statement in response to the network's claims.

The White House statement said Trump had paid $US38 million in taxes and had an income of $150 million in 2005, but did not release documents supporting its numbers. The figures were in line with what MSNBC and Johnson have reported.

In its statement, the White House blasted the broadcaster, and the media as a whole, dismissing the heavily promoted story as a ratings push.

"You know you are desperate for ratings when you are willing to violate the law to push a story about two pages of tax returns from over a decade ago," it said.

"The dishonest media can continue to make this part of their agenda, while the President will focus on his, which includes tax reform that will benefit all Americans."

The unauthorised release of federal tax returns is a criminal offence. But Maddow argued that MSNBC was exercising its First Amendment right to publish information in the public interest.

"It is not illegal," she said.

President Trump's tax details have been a source of controversy for the new leader, who at one stage said he would release his tax returns if elected.

He has since repeatedly said he would not release his personal tax details, claiming he was unable to do so because of an audit by the Internal Revenue Service (IRS). The IRS has disputed this and said there was no reason why he couldn't make his details public.

A new level of interest in the President's tax returns has developed in recent weeks, as it's believed the documents may provide further insight into his financial ties to Russia.

He is the first Presidential candidate from either of the two major parties not to open his financial records to the public since 1976.

Trump has insisted the American public wasn't interested in returns and said little could be learned from them.

The issue a major point of attack from his rival Hillary Clinton, who suggested Trump had something to hide.

The White House has not said whether or not the president plans to release his returns while he's in office.