Council owned lines company, Orion, has been accused at the High Court in Christchurch of obstructing the investigation in to the cause of the 2017 Port Hills fires.
Eighty claimants who suffered property damage want $10 million, alleging negligence by Orion and the Christchurch Adventure Park.
Opening the group's case, Craig Stevens said the Early Valley fire was started by molten metal from a faulting power pole falling on to tinder dry grass.
He says Orion's replacing of this pole just three days later, and its failure to retain crucial parts of it, obstructed the investigation.
