President Trump's conservative Supreme Court nominee Judge Neil M Gorsuch has called Trump's attacks on US judges 'demoralising' and 'disheartening'.

The comments followed Trump's increasing aggression toward the US judiciary following their opposition to his controversial Muslim travel ban. Trump's executive order banned any immigrants from seven majority Muslim countries from entering the US.

When a Seattle judge blocked the president's order last week, Trump called him a 'so-called judge' and insisted the 'ridiculous' block would be overturned.

Trump later tweeted: 'Just cannot believe a judge would put our country in such peril. If something happens blame him and court system.'

An appeal to reinstate the ban was made by the White House, but was rejected by the U.S. federal appeals court. Trump later decried the rebel judges as 'disgraceful' and 'so political'.

The comments were judged by critics to be a dangerous overreach of the executive branch, and an undermining of judicial independence and oversight.

Judge Gorsuch, made his comments in a private conversation on Wednesday with Connecticut Democrat Senator Richard Blumenthal, in which he called Trump's attacks on the judiciary 'demoralising' and 'disheartening', as the New York Times reports.

The comments were confirmed by Gorsuch's spokesman Ron Bonjean, and then by Blumenthal. 'In fact, Judge Gorsuch specifically said, "You should feel free to mention what I said about these attacks being disheartening and demoralizing,"' Blumenthal told MSNBC. This prompted a tweet from President Trump, who accused Blumenthal of misrepresenting what Gorsuch said.

Other sources confirmed Gorsuch's concern about the President's remarks, as CNN reports. Former GOP Senator Kelly Ayotte said today that Gorsuch has told senators that 'he finds any criticism of a judge's integrity and independence disheartening and demoralizing.'

However, according to Ayotte, Gorsuch 'could not comment on any specific cases and that judicial ethics prevent him from commenting on political matters.'

Republican Senator Ben Sasse of Nebraska also confirmed Gorsuch's criticism, speaking this morning on MSNBC.

Sasse said that Gorsuch 'got pretty passionate' about the issue, particularly when he was asked about Trump's 'so-called judge' tweet.

'This is a guy who welled up with some energy. He said any attack on any brothers or sisters of the robe is an attack on all judges. He believes in an an independent judiciary,' Sasse said.

Gorsuch, who is 49, was nominated for the Supreme Court by Trump last week, in a conservative selection that delighted many evangelicals. Trump said then that Gorsuch was 'as good as it gets'.