Sewage is no longer being discharged into Christchurch City and Waimakariri district rivers infrastructure damaged in the September 4 Canterbury earthquake is repaired.

Christchurch City Council water and waste manager Mark Christison said contractors had made repairs and cleared blockages which were causing discharges into the Avon and Styx rivers.

"We are pleased the work has been done so quickly - it is only two months since the earthquake and we have been able to make repairs much faster than we originally thought," Mr Christison said.

"After the earthquake there were around 2700 homes without a sewage service. At the beginning of this week, there were fewer than 70 and within the next two weeks, we hope to have every home in the city with a sewer service."

Waimakariri District Council also this week announced they would be ceasing to discharge sewage into the district's rivers.

However, Mr Christison said the sewage network in damaged areas is still fragile and if people experience any problems they should ring the council call centre and the council will investigate as required.

The Medical Officer of Health is continually reviewing river and beach water quality and is keeping users advised on recreational use.

Canterbury scientist Michele Stevenson said water quality in the region's earthquake affected rivers and estuaries have returned to pre-earthquake levels, weekly tests have indicated.

Ms Stevenson said water testing sites along the Avon/Otakaro, Styx, Kaiapoi and Waimakariri rivers, and at the northern part of the Avon-Heathcote Estuary/Ihutai had shown significantly elevated levels of indicator bacteria in the weeks following the earthquake, but testing showed these had now returned to normal levels.

"The results from this week's monitoring show that bacterial concentrations at all sites are back down to the range we have seen at these sites in the past," Ms Stevenson said. "This is really good news for all recreational water users, and is directly related to the speed at which the Christchurch City Council and Waimakariri District Council have repaired sewers and pumping stations damaged in the earthquake."

However, Canterbury Medical Officer of Health Alistair Humphrey warned the risk to water quality and public health was still higher following significant rainfall and people should avoid contact with all waterways for 48 hours after heavy rainfall.

"This caution should be taken very seriously as sewer and stormwater pipes are still under repair and rainfall can result in sewage overflows and leakage from these damaged sewers," he said. "It will be up to two years before all sewers are reinstated to their pre-earthquake state and so people should bear this longer period in mind regarding rainfall events."

Christchurch City Council also removed earthquake cordons from six Sydenham shops yesterday to improve traffic flows on Colombo St.

The cordons were put up to keep the public away from dangerous buildings, however contractors have propped verandas and strapped parapets to secure the buildings.

Meanwhile the council has deferred its decision on an earthquake rates relief package.

Mayor Bob Parker said council is committed to a fair and equitable rates relief policy,

"However, it's important that we take the time to understand all options and their implications. This is a complex issue and we need as a Council to work through the technical details before we come to a decision that will have a long-term impact."

A decision will now be made at the council's November 18 meeting.