Supreme Court nominee Brett Kavanaugh glances at reporters during a meeting on Capitol Hill in Washington. File picture: Manuel Balce Ceneta/AP

Washington - A heated session is expected Tuesday as lawmakers from the upper chamber of the US Congress hold a hearing for Brett Kavanaugh, President Donald Trump's Supreme Court nominee.

The Senate is expected to grill Kavanaugh, who will likely shift the divided court to the conservative members' favour.

Opposition Democrats and liberals fear his vote could affect rulings on hot-button topics like abortion, gun control, campaign finance laws and other issues that regularly come before the court.

Democrats last week accused the White House of blocking the full release of some 100,000 documents from Kavanaugh's time working for the government, including as lawyer for former president George W. Bush after the September 11 attacks.

"What are they trying so desperately to hide?" leading Democratic Senator Chuck Schumer asked on Friday.

Anthony Kennedy, a swing vote on the court, announced his retirement this summer, paving the way for Trump to get a second pick at a judge for the top court in less than two years in the White House.

Kennedy often elevated personal liberties over strict conservatism, putting Kavanaugh potentially to his right and making this the first time in many years a judge of one political persuasion will not be replaced by a similarly ideological justice.

The US Supreme Court is both the constitutional court and the top appeals court. Its decisions have a lasting impact on society, including historic rulings on racial segregation, abortion rights and same-sex marriage.

The eventual confirmation vote might be tight in the Senate, where Trump's centre-right party hold a slim majority, but his appointment is seen as likely.