The Red Cross has wound down its operations in Seddon after Friday's earthquake damaged homes, leaving some uninhabitable.

The 6.6 magnitude quake hit near the South Island town about 2.30pm.

Since then a swarm of aftershocks has shaken the centre of the country.

Seddon suffered the worst, with five houses damaged so badly they were left uninhabitable.

GeoNet duty seismologist Caroline Holden said yesterday had been relatively quiet compared with the aftershocks felt at other times over the weekend. "We've only had one magnitude 4-plus today, which was a 4.2 at around 2.15pm."

In the next seven days the likelihood of another magnitude 4 quake was 100 per cent, while the chance of a quake reaching magnitude 5 or above was about 82 per cent, Ms Holden said. "Large aftershocks are definitely expected in the next week."

But the chance of an earthquake of magnitude 6 or above in the next week was a mere 8 per cent, she said.

Sixteen magnitude 5-and-above and 59 magnitude 4-and-above earthquakes had hit since Friday.

Wellington City Council spokesman Richard MacLean said it was awaiting a "giant 400-tonne crane" from Christchurch to help dismantle the Luke's Lane lift shaft - initially damaged in last month's 6.5 tremor.

Wellington Fire Service said although crews were busy on Friday rescuing people from lifts and attending burst sprinkler pipes due to the movement of buildings, the weekend had been relatively quiet.

The Ministry of Education said most schools in quake-hit areas were expected to open today.

Engineers were checking school properties but so far only superficial damage had been reported.

Winemaker helpless as sav blanc drains away
A Marlborough winery chief has told of watching helplessly as up to 60,000 litres of sauvignon blanc leaked out of a damaged tank and was lost after Friday's big earthquake.

One of the Saint Clair Family Estate's three 300,000-litre stainless steel wine tanks was damaged in the earthquake and sprang a leak.

Chief financial officer Nikki De Reeper indicated yesterday other Marlborough wineries might also have suffered damage from the shake.

"I think there's quite a few of us in the district - I don't know about wine lost, but definitely tank movement."

She was uncertain what had happened to the leaking Saint Clair tank, which is bolted to a concrete base, but said that because the tank was full, the shaking had caused it to rupture - possibly the failure of a weld - near the bottom.

Some of the lost sauvignon blanc would have been bottled this week. Although a "fair whack" of wine to go down the drain, the 50,000 to 60,000 litres lost was "a small portion of what we do".

Attempts to limit the losses were at first frustrated by a power cut.

"We came back from the evacuation procedures and noticed the wine was leaking out of the tank. The guys all got together to get lines in to have it fall into other tanks but at that time unfortunately there was no power. It was just gravitational flow.

"We wanted to make sure our staff were safe first and foremost; we didn't want them in a dangerous area so we left it until Hamish [Clark, the senior winemaker] brought back [a] generator and then made sure everyone [who] should have, got checked out of the place and out of the area."

- APNZ