The men were part of a crew of seven working an excavation site belonging to Tausala Matiu Company when it caved in on them.
Three of them men were died on the spot while a fourth was admitted to hospital with serious injuries.
The chief executive of the ministry of natural resources and environment Ulu Bismarck Crawley said charges could be laid once an investigation into the incident is complete.
Ulu said the company did not have a license to excavate the land it was working on.
