Fast action on the part of Queenstown Lakes District Council contractors mitigated the impact of a wastewater leak into Lake Wakatipu yesterday (Sunday), QLDC chief executive Duncan Field said.

"At 7am yesterday our contractors received notice that there was a leak on Park Street, close to the sewage pump station. At 7.10 am they were on site," Mr Field said.

Contractors discovered a break in the rising main which meant wastewater was running from the leak, along the kerb and channel and into a mud tank, which subsequently discharged into Lake Wakatipu.

"Fortunately at that time of the morning the flow of sewage was very low, which meant that the leak was contained to around 4000 litres," engineer Martin O'Malley said.

In addition the broken pipe was not exposed which meant the wastewater was well filtered before escaping into the open.

"The area was immediately sealed off and work carried out to repair the pipe," Mr O'Malley said.

Initially the spill was clearly visible as a 20 metre plume on the lake, which dissipated with a southerly wind.

"The spill did not threaten any water intakes, the nearest being Kelvin Heights; however we have been monitoring the intakes on a precautionary basis and will continue to do so. At this stage there are no signs of any contamination and we are not expecting to see any problems," Mr O'Malley said.

On a number of occasions during the day yesterday contractors disinfected the parts of the road and verge which had been subject to wastewater flow to minimise any risk to the public.

The harbourmaster advised the organisers of a sailing regatta to stay clear of the area and signage was erected to guide pedestrian and vehicular traffic safely through the work site.

Yesterday's leak was the first problem with the pipe, installed in 1974, which is likely to be earmarked for replacement next year.

"One of the main contributing factors was wear in the pipe, combined with some ground movement which meant the pipe was no longer straight," Mr O'Malley said.

The repairs to the sewer pipe were completed by 5pm. A water line in the same area burst as the operation was being completed and the repairs on this were completed at midnight.

Mr Field expressed appreciation for the speed and professionalism of all staff involved including Lakes Contract Services, QLDC Engineering, the harbourmaster, S.J Allen, Just Dig It, Steve Rout Ltd, Neil Walker, Dakins and council staff.

ENDS

For further information please contact Martin O'Malley 03 441 0499.

By: Sarah