The White House has slammed MSNBC as "desperate for ratings" amid news the channel is preparing to release Donald Trump's tax returns.

Ahead of the slated 9pm EST (1am GMT) release of the returns, the White House released a statement saying the president had a responsibility to pay no more taxes than was legally required.

In a statement, the White House said Trump had paid $38m taxes on $150m of earnings and accused the show of breaking the law by releasing Trump's 2005 taxes.

"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," The White House said.

The statement shared figures it alleged Trump had paid, adding: "Despite this substantial income figure and tax paid, it is totally illegal to steal and publish tax returns."

Comments from the White House came following MSNBC's Rachel Maddow tweeting that Trump's tax returns would be released by the channel.

She wrote: ""BREAKING: We've got Trump tax returns. Tonight, 9pm ET. MSNBC. (Seriously)."

The journalist did not explain how the channel had managed to obtain the returns, nor which dates they would cover.

However, the promise of the long-awaited details of the president's tax returns is sure to draw a big audience, since he refused to release his tax returns during his presidential campaign, in an unusual move that prompted criticism from Democrats and members of the GOP alike.