Most of the country is under a total fire ban after weeks without rain led to tinder dry conditions.
Fire and Emergency New Zealand (FENZ) principal risk advisor Peter Gallagher told The AM Show New Zealanders weren't used to living with such high fire risk.
"If we were all living in Australia we'd be having that awareness about all these things that may cause that little tiny spark.
"That's all we're talking about - just has to be a mower blade striking a rock, or an emission from a chainsaw, something like that.
"Hot ember falling on the ground, the way these conditions are - that's what's starting these fires."
Mr Gallagher said there were two or three fires that could have become dangerous on Thursday, but they were brought under control in time.
He's urging people to think about what they're doing before any activity that could cause a fire and if possible check the website checkitsalright.co.nz.
Even if it rains, the risk is not going away any time soon.
"It's tempting when we get a couple of days of light rain to think well all of a sudden that fire danger may have gone away, bit of moisture in the air," Mr Gallagher said.
"It's going to take some quite substantial rain in a number of areas to bring the danger level down again."
It's also important to contact emergency services if there is any sign of deliberately lit fires, which Mr Gallagher said absolutely should not happen at this time of year.
"With the conditions we've got it's absolutely imperative that we just don't have that activity going on.
"If anyone sees anything suspicious, if they see smoke or flame, call 111, get help on the way. The sooner we get there, the quicker we can control it before it gets out of hand."