Marlborough Kaikoura Rural Fire Authority principal fire officer Richard McNamara said the fire had now been contained.
"We've been lucky," Mr McNamara said. "If the response hadn't been as fast as it was, the outcome could have been very different. It had the potential to run right to the top of the hill very quickly - and we all knew what would happen if it had run away on us."
Conditions are warm and breezy and the fire had previously spread quickly.
The team battling the blaze had been aided by 16 fire fighters who were taking part in a rural fire training exercise at the nearby Woodbourne RNZAF base.
"That gave us a lot of hitting power early on and it has made the difference," Mr McNamara said.
An investigation into the cause is underway with the blaze appearing to have begun very close to a walkway.
Public walkways in the area are now closed and people have been told to stay away. Access to roads in the area has also been restricted to emergency services and residents.