He said it was expected that that level of firefighting activity would continue for a further seven to 12 days.
On Friday residents from 19 houses on the island were evacuated because of a possible wind change.
They returned to their homes on Saturday.
The blaze, south of Waitangi Wharf on the main island, was sparked early on Thursday morning.
On Friday, the Defence Force sent a Hercules plane to carry out an aerial survey to help determine the scale and spread of the fire.
The Chatham Islands are about 840km east of Christchurch and consist of 10 islands, many of which are nature reserves.
About 600 people were listed as living there in the 2013 Census.