An Australian tourist shot directly in the eye with a paintball gun will remain in hospital overnight while the pressure in his eye stabilises.

The man's right eye was seriously injured when he was shot from a moving van while cycling near Hanmer Springs last night.

Police said the cyclist was about 4km out of town on State Highway 7, on his way to Nelson, when he noticed a vehicle approaching about 6.10pm.

"He was hit in the right eye by what he thought was a bird. He slowed, lost balance and fell of his bike.''

The tourist looked back and saw what appeared to be a white or light-coloured van driving away from him.

When he picked up the sunglasses he had been wearing, he noticed both lenses had come out and there was paint on the inside of the frames.

It was then the cyclist realised he was shot with a paintball gun.

The man was taken to Christchurch Hospital with a serious eye injury.

A hospital spokesman said the man was in comfortable condition, but he would remain in hospital overnight while the condition of his eye stabilised.

"He has actually been shot directly in the eye,'' he said.

"They just want to be sure that the pressure in his eye stabilises.''

The man was not angry about the incident, but he did want to ensure it did not happen again.

Police were making inquiries into the van, which was possibly lowered, including checking surveillance cameras.

Anyone with information was asked to contact Hanmer Springs police.

- APNZ