Firefighters battling the Port Hill blaze will be targeting hotspots on Sunday that were identified by overnight drone flights, Fire and Emergency New Zealand (FENZ) confirmed.
Fire and Emergency's specialist drone crew began their work after sunset on Saturday evening and early on Sunday morning a helicopter also carrying thermal imaging equipment has flown the full 24km perimeter of the fireground.
The thermal images pinpoint areas of extreme heat that could reignite, including many that are not easily spotted from the ground, according to FENZ.
There are 86 firefighters and other personnel working on the fire on Sunday, supported by diggers and bulldozers. Five helicopters are also available to offer assistance.
It comes as firefighters are making the most of a reprieve in the weather on Sunday before strong winds return on Monday.
MetService is forecasting severe northwest gale in exposed places for the Canterbury High Country, with gusts potentially reaching 130 km/h.
A strong wind warning has been issued for the area from 5am until 3pm on Monday.
Incident Controller Steve Kennedy said crews are making the most of favourable conditions before the winds are expected to pick up.
The investigation into the cause of the fire is continuing.
