Coastguards training on Lake Wanaka were the target of a laser strike earlier this week.
A laser beam was aimed at two Wanaka Coastguard boats, which were taking part in a training exercise on the lake about 8.30pm on Monday, president Jonathan Walmsley said.
It is thought the laser came from the area around Lismore Park.
The person with the laser was not found.
Mr Walmsley said one boat was slightly affected by the strike, but the skipper of the second boat was momentarily blinded.
While the strike caused no harm at the time, it was the possibility of damage which was most concerning, he said.
"You can imagine a vessel travelling at high speed at night and the person operating the vessel being blinded by a laser and them hitting something or someone and causing some serious damage."
No complaint had been made, but police were aware of what had happened, Mr Walmsley said.
In 2013, legislation was passed which meant people wanting to import high-powered lasers had to obtain authorisation from the director-general of health.
It is an offence to be in possession of a high-powered laser in a public place without a reasonable excuse.
