A leaky homes class action has been filed against cladding manufacturer James Hardie.
The construction company is accused of negligence in the design, manufacture and supply of its Harditex cladding system.
The litigation firm, Parker and Associates, said more than 500 potential claimants have come forward since the action was announced in August.
A partner, Dan Parker, said many of their claimants did not immediately realise there was water damage to their properties caused by the cladding.
He said leaky home owners should investigate to see if Harditex has been used in their houses, and can join the class action before the cut-off on 31 December.