More upheaval looms for Christchurch social housing tenants after another 31 units were doomed by the city council because of safety concerns.

The council said yesterday it was closing 17 units in its Knightsbridge Ln complex in Aranui, seven units in the 13-unit Louisson Courts complex in Opawa and seven units in the 13-unit Avonheath Courts complex in Redcliffs.

The closures come after results of detailed engineering evaluations showed the three complexes have a seismic capacity of less than 34 per cent of the new building standard (NBS).

Six Avonheath and six Louisson units had already been closed because of earthquake damage.

Council community services general manager Michael Aitken said the council was being cautious but it had made a commitment to close buildings that were assessed as below 34 per cent of the NBS to ensure the safety of tenants.

Engineers assessed the seismic capacity of the Avonheath Courts units at 21 to 33 per cent of the NBS, while all four blocks at Knightsbridge Ln were assessed at 22 per cent.

Engineers found Louisson Courts had an estimated seismic capacity of less than 34 per cent of the standard.

"There are other City Housing units available for those who wish to remain in a council-owned unit, which we hope will help to alleviate some of the disruption that will result from today's decision," Aitken said.

Knightsbridge Ln residents Hugh Allen and Dale Glendenning said the news they were losing the homes they had lived in for three and seven years respectively had come as a shock.

"We weren't expecting it at all," Allen said. "We asked last year if these places were OK and they told us they were fine."

The council has given the residents three months to vacate their units, but neither Allen nor Glendenning know where they will go and are questioning why they should continue to pay rent on their damaged units.

"They should let us live here rent-free for the next three months so we can save some money," Glendenning said.

Betty May Underwood, who moved into Knightsbridge after the February 2011 quake destroyed the council unit in South New Brighton that had been her home for 23 years, hopes a solution may be found that will enable her to stay in her home.

"I would hate to think I was on the move again," she said.

Her daughter wanted her to live with her on the Gold Coast but she did not want to leave Christchurch because her ailing husband was in a rest home.

Louisson Courts resident Brendon Collins took the news of the complex's closure in his stride.

"I was half expecting it," he said.

Collins said despite the low seismic capacity rating of the units, he felt safe in his home as it had come through the quakes well.

- © Fairfax NZ News