Consents in the region fell to 165 in September from 192 in August, which was the highest number in more than 12 months.
The value of Otago consents fell $10 million to $68 million, still the second-highest amount in the past 12 months after the $78 million approved in August.
South Island consents fell to 730 in September from 858 in August and their value fell to $265 million from $308 million.
In Dunedin the number of consents was flat at 37, in Central Otago there was a fall of two to 36, and in Queenstown Lakes consents fell to 84 from 109.
Invercargill consents bucked the trend, rising seven to 14.
Westpac industry economist David Norman said Canterbury consents fell sharply from about 555 in August to 464 in seasonally adjusted terms.
There were far fewer multi-unit approvals than in August or July. The downward trend as rebuild work wound down appeared to have resumed after a couple of chunky apartment approvals.
ASB chief economist Nick Tuffley said building consents remained highly volatile. However, the underlying trend was still encouraging.
Falls in Auckland and Canterbury consents were offset by increases in Wellington.
''Stepping back from the monthly volatility, the trend remained one of broad-based increase across the country. Strong population growth has fuelled housing construction demand.''
Looking ahead, Auckland's housing market remained supply constrained, despite the lift in housing construction.
Recent legal challenges to the Unitary Plan brought uncertainty about its implementation, which could impact developers.
Nationally, 2550 consents were issued in September, down from 2834 in August and 2811 in July.
