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.