The Christchurch City Council expects an influx of people returning to eastern suburbs in the coming days.
Many people left Christchurch after the 22 February earthquake.
Mayor Bob Parker says the Civil Defence teams working in the eastern suburbs believe that up to 40% of homes have been empty.
But a large number of people are returning now, Mr Parker says, possibly because schools are set to reopen on Monday.
The Mayor says about 56,000 properties on the eastern side of the city have now received individual inspections.