A local state of emergency has been declared for Banks Peninsula after heavy rain caused widespread flooding, slips, fallen trees and major disruption across the area.

Christchurch Mayor Phil Mauger made the declaration at 12pm, saying it was important to act early and give Civil Defence and emergency teams the authority to respond without delay.

Speaking to chrislynchmedia.com, Mauger said the declaration meant Civil Defence could “swing into action and do all sorts of things that they’d like to do,” without having to seek further permission.

“It’s giving the people that know what to do the power to do it without having to ask for permission,” he said.

He said the move allows authorities to engage resources as quickly as possible to make sure people are safe.

The state of emergency applies to Banks Peninsula only.

Mauger spent the morning in the area and said conditions in Little River were severe. He said he was able to travel as far as the township, but was told floodwaters were about 1.2 metres deep along the main street near a cafe.

“That’s what’s coming down the road at a great rate,” he said, describing water surging from the hills and surrounding catchments into Little River and nearby bays.

Although rainfall had eased in some parts, a heavy rain warning remains in place for Banks Peninsula.

Mauger confirmed there had been power and communication issues, with electricity crews unable to reach some areas earlier because of flooding.

“The power trucks were there because they couldn’t get through at that stage,” he said.

He said the state of emergency also covered concerns around communications, power, boil water notices at Wainui, damage to a bridge approach cutting off access, and ongoing slip risks.

“It might not happen instantly, but we’ve got to just keep our eye on what can happen,” he said.

Work is under way to open Lake Forsyth later in the afternoon, with diggers due to arrive after lunch.

“One thing I learned this morning is the lake is not actually as high as it was in May,” Mauger said. “But there’s so much water coming down from up in the foothills, it’s a raging torrent.”

He said longer term improvements may be needed to make it easier for water to move from the foothills into the lake.

“You get no thanks by saying, ‘Ah it’ll come right, it’ll come right.’ You’re better off to go early and let the people that know what they’re doing do what they know best,” he said when asked about the threshold for declaring a state of emergency.

The declaration is expected to remain in place for about a week.

“They normally run for a week, so at this stage that’s what we’re looking at,” Mauger said, adding that while weather conditions were forecast to improve, “they’re not out of the woods by a bloody long shot over there.”