Donald trump is expected to nominate amy coney barrett to the us supreme court, according to media reports, in a move that would decisively shift the countrys highest bench in a conservative direction if she is confirmed.

Ms barrett, a 48-year-old federal appeals court judge, is favoured by religious conservatives and anti-abortion campaigners for the vacant seat left by ruth bader ginsburg, the liberal icon and womens rights pioneer who died last week.

Senate republicans have indicated they will move quickly to confirm mr trumps choice before the presidential election in november, despite blocking barack obamas supreme court nominee in 2016 on the grounds that it was an election year.

Mr trump is set to make an official announcement at the white house on saturday, the first step in what will be an accelerated process to deliver to conservatives a powerful 6-3 majority on the supreme court.

The president on friday evening told reporters that he had made up his mind but did not confirm that he had chosen ms barrett. i havent said it was her but she is outstanding, he said.

Mr trump, who was in florida for a rally on thursday night, said he had not met barbara lagoa, the florida-based appeals court judge who was seen as the other lead contender for the vacancy.

The nomination comes at a critical time for mr trump who is trailing in the polls against joe biden, his democratic rival for the white house. the president has over the past week stressed his record of installing conservative judges on the federal bench at political rallies in an effort to energise his base ahead of the election.

While some conservatives viewed mr trump as a new york liberal four years ago, they gambled on him as the republican presidential candidate after he vowed to pick conservative supreme court justices from a list that he made public during the gop primary race.

The president has the chance to place a third justice on the high court, which has not happened since ronald reagan. his party is hoping that his nomination of another justice coupled with democratic opposition will mobilise republicans to vote on november 3.

Mr trump this week also made clear that he wanted the senate to approve his nominee as quickly as possible out of concern that the court would have to adjudicate a contested election result.

Ms barretts confirmation could herald dramatic shifts in law towards restricting abortion, expanding gun ownership rights and limiting the power of regulatory agencies.

She was previously appointed by mr trump to serve on the chicago-based 7th us circuit court of appeals in 2017. a devout catholic, she had spent much of her career as a professor at notre dame law school in indiana.

At her confirmation hearing in 2017, democrats questioned whether she could separate her duties as a judge from her faith, citing an academic article she had authored that grappled with that question.

Dianne feinstein, the top democrat on the senate judiciary committee, declared that the dogma lives loudly within you, a phrase quickly claimed by conservative activists as a badge of pride and used on merchandise.

Ms barrett would be all but certain to be confirmed. senate republicans, led by mitch mcconnell, have a 53-47 majority in the chamber and only two republicans have voiced any dissent about installing mr trumps nominee before the election.

Her ascension to the high court would be the capstone on a remarkable transformation of the federal judiciary during mr trumps presidential term. in addition to the two justices he has named to the supreme court, mr trump has nominated almost a third of all active appeals court judges.