Conservative United States Supreme Court Justice Antonin Scalia has died, aged 79.

"On behalf of the court and retired justices, I am saddened to report that our colleague Justice Antonin Scalia has passed away," Supreme Court Chief Justice John Roberts said in a statement confirming the death on Saturday evening.

"He was an extraordinary individual and jurist, admired and treasured by his colleagues. His passing is a great loss to the court and the country he so loyally served. We extend our deepest condolences to his wife, Maureen, and his family."

Scalia's death was first reported by the San Antonio News-Express, who said he had apparently died of natural causes while visiting a luxury resort in West Texas.

Appointed to the top US court in 1986 by President Ronald Reagan, Scalia was known for his strident conservative views and theatrical flair in the courtroom.

President Barack Obama extended his condolences to Scalia's family.

The president will face a stiff battle to win confirmation of a nominee to replace Scalia, with Republicans likely to delay in the hope that one of their own wins the November election.

But if Obama does successfully nominate a replacement before his term ends in January, it could tilt the court to the left for the first time in decades.

"Justice Scalia was an American hero. We owe it to him, and the nation, for the Senate to ensure that the next president names his replacement," Senator Ted Cruz of Texas, a Republican presidential candidate, said on Twitter.

The nation's highest court is set to decide its first major abortion case in nearly 10 years as well as key cases on voting rights, affirmative action and immigration.

Source: Agencies