Upper North Island struck by swarms of crickets

Huge swarms of crickets are crawling out of the ground in the upper North Island.

It's not the apocalypse, as many rural residents are joking, but it is the biggest cricket invasion in many years.

Peter Brennan got a bit of a shock when his evening TV programme was interrupted by what he thought was the weather.

Instead, it was crickets.

"It sounded like a small hailstorm, which made no sense on a hot, humid, sticky night," he said.

"We pulled the curtains back and, voila, there were all these crickets swarming against the windows."

It's the first time in 20 years' living north of Auckland in Kaukapakapa that Mr Brennan has seen such huge numbers of the bugs.

"In the space of 24 hours, we went from no crickets to thousands of crickets," he said.

In rural Waikato too, residents spent Wednesday morning cleaning up after a major infestation.

Experts say there's an explosion of the native black field crickets, because a warm summer creates ideal hatching conditions.

"The other thing is they're getting stirred up by all the rain over the last few days - it's just flushing them out of their hidey holes," said entomologist John Early.

For now, they're harmless, but the crickets could yet cause a headache for farmers. 

Because the crickets' favourite food is grass, if they stick around for another week or two, they could end up competing with cows for food.

And with huge numbers being reported, the crickets could stick around that long.

The advice is you can't stop them, just wait it out.