The source of a neon-green liquid flowing into Queenstown's Lake Wakatipu remains a mystery

It's being suggested the substance first found in Horne Creek near the library could be vehicle coolant or marker dye.

A pollution response team from the Otago Regional Council is waiting for the results of water samples.

Regulatory General Manager Richard Saunders says it's too early to speculate if there's been any environmental damage - until the source is identified.

Queenstown Lakes District Council says it could take weeks to confirm this.

CCTV footage showing the liquid entering the creek on Sunday is being reviewed.