A freak summer storm has forced 14 skydivers to make an emergency landing at St Kilda Beach in Victoria.

Five people remain in hospital after 54 knot winds - whipped up in less than two minutes - forced some of them to make a water landing at 3pm.

Locals watched in horror as the winds and squall caused the parachutes to move and flip wildly.

Many rushed into the water to help after one man was dragged under the surface by his parachute.

It took everything they had to keep his head above water and drag him to the safety of the Sea Baths.

The skydivers had jumped from 14,000 feet in seven pairs.

The company said they had left the plane before the weather sprung up.