The US Supreme Court heard arguments Wednesday in a case about legal provisions intended to prevent the "straw" purchases of guns by one individual for other buyers.

In the case -- the second taken up by the justices in a week concerning gun laws -- former Virginia police officer Bruce Abramski was a straw purchaser who bought a gun for an uncle.

Although both men were legal gun owners, Abramski indicated on a federal form that he was the gun's actual buyer.

At the Supreme Court, his lawyer Richard Dietz said the transaction was legal because the men's legal and mental background allowed them to purchase a firearm.

"It doesn't matter if the ultimate transferee is Al Capone or somebody else," said Justice Elena Kagan.

"The purpose is to take away guns from (persons with) mental illnesses."

Justice Samuel Alito also stressed that controls meant to keep guns away from criminals and the mentally ill would be "meaningless" when the purchaser who undergoes background checks is not the final user.

US Attorney Joseph Palmore said the plaintiff's argument "would greatly impair the ability of ATF (the Bureau of Alcohol, Tobacco and Firearms) to trace firearms and to have an accurate record of who that first purchaser of the firearm was" in order to prevent "anonymous sales of firearms".

In a first case take up January 15, the Supreme Court addressed whether carrying a weapon could be authorised at the federal level if there were a state-level conviction for minor domestic offenses.

In both cases, decisions by the court are expected by the end of June.