A sprawling network of crime cameras will be possible in Christchurch by the end of the year.

New technology developed by the Christchurch City Council will mean a limitless number of security cameras can be added to the surveillance network within the four avenues at half the total cost.

Civil libertarians are wary of increased cameras on city streets on top of their burgeoning use across society from buses to schools.

Christchurch's existing network of 30 cameras has been unable to expand since it was established 11 years ago due to the cost of using Telecom lines to transmit images to the police control room.

The network uses Telecom fibre optic lines to send images to police headquarters on Hereford Street. The new system, set for completion by the end of the year, will send images using a network of copper wires built by the council from the 1930s to control traffic lights.

The move means there is no limit to the number of security cameras in Christchurch and the annual crime camera budget of $100,000 can be cut in half.

The network has been trialled by the council and police over the last six months with two new cameras on Cashel Mall and another trained on the Oxford Terrace Strip from the roof of police headquarters.

Christchurch central police area commander, Inspector Gary Knowles, said the system would give police greater reach and mean cameras could be deployed at trouble spots.

"We are looking to get more of them and looking at the possibility of transporting them to trouble spots ... we will be able to put cameras further out in the suburbs. We have the option to be more mobile and flexible. We would like to get more permanent ones and expand them across the district," said Knowles.

Retailers and bar owners would also welcome more security cameras.

Clive Weston, owner of Coyote bar and restaurant on the Strip and member of the Central City Business Association, backs the plan.

"Anything we can do co-operatively that will reduce the perception of Christchurch being an unsafe place will help," he said.

Minit Solutions manager Daniel Kennedy, on City Mall, said more cameras would "make people think twice about taking stuff".

The crime camera network is funded by the council and monitored by police and volunteers. Once the new system is complete, Christchurch City councillors will decide if more security cameras are needed.

The move comes as the number of security cameras in Christchurch is on the rise.

A network of 558 security cameras on Christchurch's bus system was completed in July last year.

Every bus in Christchurch now has two cameras, which save footage to a hard drive on board.

Security cameras are also common in retail malls, shops, at some schools and in taxis.

The rise of cameras in Christchurch reflects rapid international growth abroad. In Britain there are an estimated 4.2 million security cameras, which have often played a crucial role in solving high profile crimes. Just last week, British Police scoured CCTV footage in the hunt for culprits of a London car bomb plot.

Canterbury Council for Civil Liberties spokesman Graeme Dunstall said cameras should only be used in trouble spots.

"I am uneasy about the growth of a surveillance society. Our privacy is precious and needs to be protected as far as it can be. Cameras should only be in clearly demonstrated areas of disorder or places where people are being victimised," he said.

Knowles said security cameras were just a modern part of life.

"People who have done nothing unlawful have nothing to fear. I think people will accept them as a modern part of life. It would be naive to think you will not be tracked by camera."