Elon Musk's SpaceX called off the latest test flight of its Starship rocket just before its scheduled launch on Monday, citing an unspecified problem with the behemoth spacecraft.

"Standing down from today's flight test attempt," SpaceX posted on X, also owned by Musk. "Starship team is determining the next best available opportunity to fly."

The world's biggest and most powerful rocket was set to take off with no crew at 6:45pm local time from SpaceX's Starbase facility in Boca Chica, Texas.

A rescheduled launch has yet to be announced, though SpaceX employee Dan Huot said it was expected "to be about 24 hours" during a live feed of the event.

The flight will be Starship's eighth orbital mission overall and first since a dramatic mid-air explosion over the Caribbean during its last trial.

Standing 123 metres tall, Starship is designed to eventually be fully reusable and plays a crucial role in Musk and SpaceX's vision of colonising Mars.

Meanwhile, Nasa is awaiting a modified version of the rocket for its Artemis program, which aims to return astronauts to the Moon.

The US Federal Aviation Administration grounded Starship after its previous flight on January 16 ended with the upper stage disintegrating in a fiery cascade over the Turks and Caicos Islands, prompting clean-up efforts for fallen debris.

For the upcoming flight, SpaceX says it has introduced numerous upgrades to the upper-stage spacecraft, enhancing its reliability and performance.

The mission, expected to last just over an hour, includes another attempt to catch the booster stage using the launch tower's "chopstick" arms – a feat SpaceX has successfully executed twice, including in the last flight.

Meanwhile, the first commercial mission of Europe's new heavy-lift rocket Ariane 6 was called off minutes before it was scheduled to launch, due to an "anomaly" on the ground.

It was the latest of several postponements for the rocket as Europe seeks to secure independent access to space. (AFP)