A jet skier is in Tauranga hospital after his watercaft exploded beneath him at the Kaituna Cut near Maketu this afternoon.

The man aged in his 20s was thrown several metres into the air by the explosion, which happened about 1pm, when he attempted to start the jet ski, says Maketu Volunteer Fire Brigade Chief Fire Officer Shane Beech.

Maketu fire fighters attended a jet ski explosion today

There was one person on board at the time. He had just launched it into the water and fired up the motor when it exploded.

'It appears maybe a busted fuel line may have allowed fuel to escape into the hull of the jet ski and the ignition source was probably more than likely a battery or a short somewhere,” says Shane.

The force of the blast has pretty well blown the jet ski into two pieces.

'He got blown into the air quite some distance and is suffering bruising and possible damage to his back,” says Shane.

'Burn wise he's got off pretty lightly. He was actually in the water. He was sitting on the seat, the seat's gone boom! He's gone God knows how many metres up into the air and then landed back into the water.”

The man is from Rotorua. Shane says the jet ski was rigged for fishing with a chilly bin and fishing rods.

'He had a mate with him who's following him to hospital and taking what's left of the jet ski home, says Shane.