The large forest fire in Marlborough that has seen a dozen homes evacuated may not be brought under control until Saturday night, say firefighters.
Today, 50 firefighters, 13 tankers, 10 earth-movers and 10 helicopters will continue to battle the blaze.
An extra 12 fire crews had to be brought in last night to help battle the fire in the Waikakaho Valley.
During the past two days the fire has burnt through about 400ha in the Waikakaho Valley, north-west of Blenheim, and warm weather today is not expected to help.
National Rural Fire Authority incident controller Rob Hands said it would take some time to put the fire out.
"The fire itself will be a week or more I'd imagine, but we're hoping the containment of it, the control of it should be tidied up by tomorrow night and then we can just go and do the carry on with the mop-up for the next week or so."
Mr Hands said fire crews were working 12-hour shifts as they fought the blaze.
He said the plan was to keep the crews working on the fire for three days and then "get help from out neighbours".
Half of the 24 houses in the valley had been evacuated by yesterday afternoon. Mr Hands told Morning Report another six were evacuated at 2am today as the fire spread.
"(It's) right up against the boundaries of particularly three properties at the moment, and that's what the ground crews are protecting," he said.
"We're in the process of putting the aircraft in the air to ... support them."
A handful of homes in the valley were still occupied but he said the police did not consider them to be at risk currently.
Forestry block destroyed
Di Sutton said her 67ha forestry block had been destroyed.
She did not live near the block so had not been evacuated but her son and his family had and were staying with her - as were their pig dogs and pet lambs.
The cause of the fire remained unclear but Sue Huddleston - the co-owner of a forestry block near the blaze - said she believed it started on a forestry skid site.
Mrs Huddleston said their forestry block - which occupied more than 200ha - was about eight or nine years from harvest.
They could only hope the block remained out of the fire's path, she said.
The cost of the blaze has been estimated at $3 million-plus.
Meanwhile, the SPCA has been helping with shelter and transport for any animals affected by the fire.