Democratic senatorsduring a congressional hearing launched their campaign against Judge Neil Gorsuch, President Donald Trump's nominee for the vacant Supreme Court seat.

Gorsuch, 49, appeared on Monday for the first time before the Senate Judiciary Committee to ask senators to vote for him and allow him to take a lifelong seat on the high court replacing conservative Justice Antonin Scalia, who died in February 2016, Efe news reported.

Gorsuch stressed "the importance of an independent judiciary" in his opening statement to the committee.

"Under our Constitution, it is for this body, the people's representatives, to make new laws. For the executive to ensure those laws are faithfully enforced. And for neutral and independent judges to apply the law in the people's disputes," he said.

During his 13-minute remarks, the Judge – who serves on the Denver-based 10th US Circuit Court of Appeals – made no reference to Trump's attacks on other judges but directed some of his remarks at the rest of the country's judiciary and thanked the nation's judges for their work.

Democratic senators have asked Gorsuch to publicly take a position on Trump's attacks on the judges who have blocked his executive order temporarily prohibiting US entry to refugees and nationals of six Muslim-majority nations.

Specifically, one of the Democrats' objectives in these hearings is to evaluate Gorsuch's willingness to oppose Trump, given that the Supreme Court potentially will have the last word on measures that the president is proclaiming by decree, including the immigrant and refugee travel ban.

In addition, during the hearing, Democratic lawmakers criticised Gorsuch for the rulings he has issued in favour of large companies.

Meanwhile, Democrats portrayed Gorsuch as a coldhearted magistrate who interprets the law literally, while Republicans praised his legal preparation and expressed support for some of his rulings, including the one he issued in 2013 against former President Barack Obama's healthcare reform.

To gain confirmation, once moving through the Judiciary Committee, Gorsuch will need 60 votes in the full Senate, a barrier that could be difficult for him to overcome since Republicans only hold 52 seats and would need the support of at least eight Democrats.

That support could be difficult to muster because Democrats are still angered over the Republicans' decision not to consider Obama's nomination of Judge Merrick Garland for the high court seat, a move that was ignored by the Republican lawmakers using the argument that it made no sense to approve such a nominee in an election year.

Given these difficulties, Trump has asked Republican Senate Majority Leader Mitch McConnell to resort to the so-called "nuclear option," a rule approved in the past by Democrats to enable them to approve bills or nominations by a simple majority of 51 votes instead of a super-majority of 60.

The committee will meet again at 9.30 am, on Tuesday and is scheduled to hold hearings until Thursday, after which the full Senate vote on Gorsuch's nomination could come in early April.