It's a bird. It's a plane. It's a ... flyboarder

A CROSS between a jet-ski and a jet-pack helped propel Peter Hendra high above the water at St Kilda beach on Thursday.

Mr Hendra was demonstrating the device for business partners who plan to offer flights to adventure seekers out of the St Kilda Sea Baths within weeks.

The flyboard is attached to a user's feet and connected to a jet-ski via a hose. Seawater is propelled up the hose, lifting the user into the air.

Mr Hendra competed in the first flyboard world cup in Doha in October and is the Australian distributor of the device, which to date has only been offered for hire on the Gold Coast.

Sea Baths marketing manager Travis Atkins said Mr Hendra's demonstration attracted many onlookers who clapped and gasped as they watched the master at work.

After watching the flyboard in action he said he was assured it would not disturb other beachgoers.

''It doesn't go fast and it's not loud. Everyone has concerns about jet-skis but this doesn't fall into that because the jet-ski is on idle, so the noise is low,'' he said.

The flyboard's makers say it takes about 20 minutes for new users to find their balance and start flying freely, with the help of an instructor.