Pilot Richie McCaw maps fire by helicopter

Among the 15 or so helicopters and fixed-wing aircraft helping to fight the fire engulfing the Port Hills is one piloted by a double Rugby World Cup winner.

Richie McCaw is taking observers up above the hills who then map the fire and relay its position to those on the ground.

"I've seen a lot of burning. The crazy thing with fires is, we thought it was under control yesterday and at 3 o'clock the wind got up and it got going again, it's pretty horrible," McCaw told RadioLIVE's Alison Mau.

McCaw has been flying missions since the fires began in earnest on Monday, but says the chopper pilots using monsoon buckets are far more skilled than he is.

"You can see the guys with the buckets getting down in amongst it, it's pretty tricky stuff, so they need to be pretty onto it.

"It takes a while to get up to that sort of level, I'm just learning."

The 148 test veteran says that apart from the fire, there's a lot of aerial traffic to look out for as well.

"It's busy, because the big thing is thinking about the fire, but then you've got to look after yourself too. So there's a lot of chatter, but the guys are all pretty good at what they're doing."

McCaw says he plans to continue flying mapping missions until the fire is put out for good.

"We'll have helicopters here right until the end I'm picking. The big thing will be hotspots from here and that always takes a lot longer."