A nearby resident, Johannes Stapper, complained to the Otago Daily Times the spraying ''just a few metres away'' from the lake was ''just plainly wrong and does not support our pure New Zealand green image''.
The 1ha vacant site, across Lakeside Dr from the lake, is owned by the Infinity Investment Group, which employed Dunstan Sprayers, of Alexandra, to do the work.
Dunstan Sprayers spokesman Mark Edgar told the ODT the work last week was carried out in accordance with the Otago Regional Council's water plan.
Mr Edgar said the spray used was Roundup and the work was a ''very minor touch-up'' after a bigger spray programme on the site last year.
However, Mr Stapper, who took pictures of the spraying, described it as a ''disgusting sight''.
''As you can see ... this guy just randomly sprays the poison all over the place, even straight into the little pond, which has a stream going directly into the lake.''
The correct procedures for the use of herbicides in circumstances where they enter water are specified in section 12.7.1.3 of the council's water plan.
