Lack of rain is beginning to take its toll on Christchurch and Banks Peninsula, with groundwater levels at record lows and rivers and streams drying up.

Low rainfall over the past few months has also left the Port Hills and Banks Peninsula drier than they were at the height of the summer, raising concerns about the fire risk.

According to NIWA's National Climate Centre, Christchurch only had 15 millimetres of rain in April, 34 per cent of what it would normally get.

Christchurch City Council Reticulaton Manager Rob Meek said the Council was investigating the introduction of water restrictions in Banks Peninsula.

"The summer and autumn months have been very dry in Christchurch, and particularly Banks Peninsula. The low rainfall throughout Canterbury has large implications on the extraction and delivery of water to Banks Peninsula.

"Stream flows are currently around a third of what they were at the start of the year and half of what they were at this time last year. If the stream flows drop any lower and are not replenished by rain events, the Council may have to move to implement water restrictions," Mr Meek said.

The networks that were most at risk were Duvauchelle, Takamatua and Akaroa.

"We are currently working out the stream flows for all streams in Bank Peninsula to decide whether restrictions are needed, but the point we would make is that this is not an issue caused by residents water usage, it is the result of weather and natural events,'' Mr Meek said.

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Environment Canterbury (ECan) Groundwater Science Manager Carl Hanson said Christchurch's groundwater levels were at record lows.

Not enough rain had fallen last winter to provide much recharge to the groundwater system and if Christchurch had another dry winter, groundwater levels would continue to fall.

"What is needed to restore base flow to our spring-fed Christchurch streams is a wetter-than-average winter,'' Mr Hanson said.

Christchurch City Council Acting Principal Rural Fire Officer Paul Devlin said conditions on the Ports Hills and in Banks Peninsula were drier now than at the height of the summer.

"It may feel autumnal but the reality is the Port Hills and Banks Peninsula are as dry now as they were at the height of the summer and the fire risk is very high,'' Mr Devlin said.

It was important that people living on the Port Hills and in rural areas minimised the risk to their homes by keeping a defendable space between their home and vegetation.

If possible they should maintain a mown grass area that would slow the travel of the fire and buy time for firefighters to protect their house, if possible, or allow the owners to escape safely.