Chaos at Christchurch Airport overnight after 17 flights were diverted to the Garden City due to wild weather in the north.

The Auckland Airport runway has reopened this morning after being cleared of debris.

Ignacio Jojoa Duran ended up in Christchurch after his flight from Wellington to Auckland was diverted there.

He says when he arrived it was mayhem.

"There were at least 300 people in the queue, there was no help or direction from anyone. There were only two people at the counter all night."

He ended up staying at the airport overnight and says the earliest flight to Auckland he's been offered by Air New Zealand is at 7pm via Palmerston North. 

Meanwhile, driving conditions on Alpine passes in the South Island are already treacherous.

ZB caller Wayne Harris is on his way to Christchurch from Greymouth.

He says the grit trucks are out - and snow showers have seen his temperature gauge plummet to zero.

"Between the top of the Porters and around Lake Lyndon, right back to to Pearson there it's as slippery as a politician. You don't need blimmin' chains yet, but I think by the end of the day you probably will."