Extra funding to clear lagarosiphon from boat ramps around Cromwell will help control the invasive weed in Lake Dunstan, those involved say.

A statement from Land and Information New Zealand (Linz) said $210,000 would be spent on control work in Cromwell this financial year.

This was up from $150,000 in 2017-18.

Last financial year the money came from Linz ($75,000), the Otago Regional Council ($25,000) and Contact Energy ($50,000).


This financial year Linz will provide $125,000, the regional council $25,000 and Contact $60,000.

A Linz spokesman said lagarosiphon control work around boat ramps was "not a new thing", but would have a "greater focus" this year through the extra funding and additional boat ramps were being included in the programme.

The money would allow commercial divers to remove weed from around boat ramps, which improved the effectiveness of the control programme.

Herbicide spraying would also be done from boats and helicopters, and a cutter would be used to slice weeds away from the surface.

Popular recreational spots such as the Old Cromwell Historic Precinct lakeshore, and the Bannockburn inlet, would also have extra control work done, Boffa Miskell biosecurity programme manager Marcus Girvan, who was working on behalf of Linz, said.

About $90,000 of this year's funding was spent before Christmas, and diquat herbicide treatment - both helicopter and boat spraying - of key sites was scheduled to be carried out late summer/early autumn, if conditions permit.

Guardians of Lake Dunstan chairman Glen Christiansen said the funding was "good news" for users of Lake Dunstan.

"While there is a significant amount of lagarosiphon in Lake Dunstan, focusing on high use areas will improve the experience of people using the lake for swimming and boating."