Meridian Energy's Christchurch-based call centre is urging customers from outside the region to put off calling till later in the week while the team supports those affected by Saturday's earthquake.

Meridian's General Manager of Retail, Bill Highet, says the call centre is operating with a reduced number of volunteer staff and the main priority in the next few days is to help customers affected by the earthquake.

"At the moment about 3,500 Canterbury households are without power. Network companies Orion and Mainpower are both doing a great job at restoring the power and we are doing everything we can to support them in their work. It must be frustrating for them to have to repair some faults more than once due to water damage, after shocks and gale force winds."

Bill says Meridian is informed that more faults to power lines are expected in the coming days and weeks due to the fragile nature of parts of the electricity network.

"We are fielding calls from customers who want to know when their power will be back on and other urgent power issues. This is our priority and we want to ask our customers from outside Canterbury with general enquiries not to call us until Thursday or Friday so that we can keep our phone lines open to support customers with urgent issues."

As well as those affected by the earthquake, the Meridian call centre remains committed to assisting all customers from around New Zealand with any urgent enquiries they may have.

Meridian mobilised to support the region on Saturday when it opened its call centre for six hours, supported by staff volunteers from across the company's business units. The team handled around 120 emergency calls immediately following the earthquake.

"It's a very difficult time for everyone in Canterbury regardless of whether you have your power back on or not and we are doing absolutely all we can to ensure all our customers' needs are taken care of," said Bill.

As advised by Civil Defence and lines companies, customers seriously affected by power cuts should make alternative arrangements with friends or relatives who do have power.

Meridian's Manchester Street office is closed and suffered minor damage from the earthquake. Anyone wanting to pay their bill can do so at NZ Post or Westpac Bank.

Meridian is the largest electricity supplier in Christchurch and Canterbury.