"The strength of the wetland is provided by wire ropes inside the structure, however, the edge could be vulnerable to intentional damage."
Mr Oldham said the wetland was in a shallow part of the lake with several rocks nearby, which generally made it unsuitable to navigate around and posed no hazard to water craft observing the shoreline's required 5 knot speed limit.
He said a crew inspected and secured the floating structure two weeks ago.
The damaged pieces had been secured by rope in the meantime and posed no threat to the environment.
Rotorua Lakes harbour master Pererika Makiha said the person responsible for the damage to the wetland should be made accountable.
He said if the damage was proven to be deliberate and the culprit was known "we would certainly be taking action against the skipper".
Mr Oldham said permanent repairs would be carried out as soon as material arrived from the United States. Discussions are being held with the contractor to retain spare material on-hand to undertake immediate repairs as the wetland is covered by a maintenance contract.
The wetland which is believed to be the world's largest man-made floating wetland cost about $900,000.
Its purpose was to remove excess nitrogen and phosphorus from Lake Rotorua and to double as a tourist attraction with the native plants sown to spell out Rotorua.
The wetland has been moored in a bay at Sulphur Point since December 2012 to allow the plants to establish themselves before being moved to its final resting place opposite the airport in February 2014.
Residents who notice any further damage to the wetland should ring (07) 348 4199.
