Fletcher Building, which is under investigation for the way it handles asbestos it finds in Christchurch, insists it is treating the hazardous material responsibly and effectively.
WorkSafe has applied to the District Court in Christchurch for an extension of time to complete a fifth investigation into the company.
The previous investigations brought no charges.
WorkSafe is examining how Fletchers goes about containing any asbestos it finds in the houses it repairs.
Fletcher Building said it had engaged with the health and safety auditor since the home repair programme began over how it handled all hazards, including asbestos.
Earthquake Recovery Minister Gerry Brownlee said he wanted to see better co-ordination between all those involved.