Twenty more moons have been discovered orbiting Saturn, giving the ringed planet 82 — at very least — scientists have revealed.

The discovery establishes Saturn as the planet in our solar system with the most moons, surpassing Jupiter's 79, according to astronomer Scott Sheppard of the Carnegie Institution for Science.

About 100 even tinier moons may be orbiting Saturn, still waiting to be found, he said.

Key points: Most of Saturn's new moons are about 5 kilometres in diameter

Most of Saturn's new moons are about 5 kilometres in diameter One of the scientists who was part of the discovery described Saturn as "the true moon king"

One of the scientists who was part of the discovery described Saturn as "the true moon king" The moons are remnants of the objects that helped planets form, meaning they could give more insight into how planets came to be

The newly discovered moons, each barely 5 kilometres in diameter, are miniscule when compared with Saturn's biggest moon, Titan, which is more than 5,000 kilometres in diameter.

"It was fun to find that Saturn is the true moon king," Dr Sheppard said.

Dr Sheppard and his team used a telescope in Hawaii to spot Saturn's previously unseen moons over the summer.

Astronomers have pretty much completed the inventory of moons, Dr Sheppard said, adding that future larger telescopes would be needed to see anything smaller.

It is harder spotting mini moons around Saturn than it is Jupiter, Dr Sheppard said, given how much farther Saturn is.

A diagram showing the orbits of the 20 newly discovered moons around Saturn. ( Supplied: NASA/JPL-Caltech/Space Science Institute )

"So seeing that Saturn has more moons, even though it is harder to find them, shows just how many moons Saturn has collected over time," he said.

These baby moons may have come from larger parent moons that broke apart right after Saturn formed.

Seventeen of Saturn's newly discovered moons orbit the planet in the opposite, or retrograde, direction.

The other three circle in the same direction that Saturn rotates and are so far from Saturn that it takes them two to three years to complete a single orbit.

"These moons are the remnants of the objects that helped form the planets, so by studying them we are learning about what the planets formed from," Dr Sheppard wrote.

Just last year, Dr Sheppard found 12 more moons around Jupiter and the Carnegie Institution had a naming contest for them. Another is planned for Saturn's mini moons.

The jury is still out on whether any planets beyond our solar system have even more moons.

For now, Saturn has the most known moons.

The announcement came from the International Astronomical Union's Minor Planet Centre.

AP