President Joe Biden has surpassed a milestone 200th appointment to the federal judiciary as the US Senate confirmed two more of his nominees, exceeding his Republican predecessor Donald Trump's pace even as the clock ticks toward their November 5 election rematch.

Reaching this number at this point in his presidency is evidence, according to Biden's allies, that he may achieve a goal his fellow Democrats not long ago fretted could be out of reach – matching Trump's tally of 234 judges appointed to life-tenured positions on the federal bench in four years in office.

Challenges in confirming judicial nominees in the Senate, where Democrats hold a slim 51-49 majority, had left Biden behind Trump's pace at the start of this year. In fact, Democratic Senator Dick Durbin, who chairs the Senate Judiciary Committee that reviews such nominations, had previously called reaching the 200 mark a year-end goal.

Instead, Biden reached the 200 milestone when the Senate voted 66-28 to confirm US Magistrate Judge Angela Martinez as a federal district court judge in Arizona and then hit 201 when the chamber voted 50-44 to confirm California state court Dena Coggins as a federal district judge.

Biden called crossing the 200 mark "another milestone in the effort to protect the freedoms and liberties of all Americans", and pledged to nominate more judges.

"There is more work to do," Biden said.

One way Biden has managed to surpass Trump's pace has been to cut deals with Republican senators to fill vacancies at the trial court level in their home states. That means Biden has sometimes picked compromise, moderate nominees rather than judges more to the left as he might prefer.

Trump, with the Senate then controlled by Republicans, appointed the second-highest number of judges on record in a single term in office, behind only Jimmy Carter. Biden is nearing Trump's tally despite inheriting less than half as many vacancies to fill when he took office as Trump had.

Durbin said Senate Democrats have "done better than I expected" in confirming Biden's nominees and that reaching Trump's tally is possible now, though hurdles remain.

"I'm going to keep pushing forward as long as we have good nominees that I can send to the (Senate) floor for consideration," Durbin said.