An investigation is under way after a cleaning contractor was caught dumping dirty water from the floor of one of the country's most highly rated "green" buildings into the Waitemata Harbour.

The cleaner, contracted by Britomart Group, was using a ride-on scrubbing machine to clean the floor at the Atrium on Takutai shopping gallery on Monday night.

Once he was finished, he hopped off the machine before dumping the waste into a street stormwater drain 100m from the harbour edge.

Auckland councillor Chris Darby said he was appalled to see the blatant dumping of dirty water outside the upmarket food and shopping gallery, which boasts the country's largest "green walls" and lies between five-star green office towers.


Mr Darby photographed the incident and has laid a complaint which is being investigated by the council's pollution compliance officers.

Precinct owner Britomart Group blamed the incident on a new employee of the cleaning contractor not knowing the protocols for disposal of dirty water.

"We believe this to be an isolated incident," said group marketing director Sarah Hull.

Several waste disposal facilities were provided on site.

United Cleaning Services regional operations manager Salesh Mudaliar said the machine attendant was standing in for a colleague who was on sick leave.

The machine uses mechanical action and hot water pressure instead of chemicals.

Daniel Sansbury, who is acting manager of the council's natural resources and specialist input unit, said the machine collected its own waste.

This should be emptied in an appropriate container and disposed of at a waste facility, or through the wastewater system, with the agreement of Watercare Services.


Fines of up to $1000 could be issued for discharging contaminants to the stormwater system and people seeing discharges should call the Council Pollution Hotline.