Since the February quake, 4900 people have left Christchurch, compared with 3000 during the same period last year.
The chief executive of the Canterbury Employers Chamber of Commerce, Peter Townsend, says the figures are disappointing but not surprising.
He says he still thinks the city is looking at the loss of 8000 people out of a population of 400,000, and with 30,000 jobs required for next year's rebuild, "ahead of us we have the possibility of a large influx of people".
The number of people making the move to New Zealand, either permanently or long-term, rose last month for the first time since the February quake.
Figures just released by Statistics New Zealand show a net gain of 200 migrants in August.