Operators of New Zealand's biggest wind farm, near Wellington, have been told it is still too noisy at times.
However it has been shown that overall noise levels from Project West Wind are well within limits established under its resource consent.
The 143-megawatt wind farm between Wellington and the west coast at Makara began generating electricity last year, after a lengthy battle between Meridian Energy and residents who opposed it.
Since then, noise levels have been monitored by two consulting firms, Wellington City Council and Meridian Energy itself.
They found overall noise levels came within agreed guidelines, but there was an extra level of deep electrical hum at one site which pushed its noise reading past approved limits.
Meridian Energy spokesperson Alan Seay says the use of sound absorbers and computer software has fixed this.
Wellington City Council says there'll be further monitoring to make sure the noise problem has been dealt with. Planning Compliance Manager Matthew Borich says it needs to be ascertained that the hum has been removed.