Nationally, the index for May rose 1.5 points to 58; with readings above 50 showing expansion and below signalling contraction, the BNZ-Business New Zealand performance of services index data showed.
The northern North Island registered 59.6, lower North Island 55.7, upper South Island 58.1 and Otago Southland declined 1.5 points to 50.5.
Otago-Southland Employers' Association chief executive John Scandrett said the southern region was sitting ''right on the 50-point fence'', which meant a reasonably equally balanced mix of sub-sector sentiment flowing from the monthly survey.
''And that is precisely what we've got,'' he said.
''Tourism and wholesale operators are split on results, against anticipated activity levels, and while construction-based feedback is quite positive, the retail sector has overall presented negative comment,'' Mr Scandrett said in a statement.
He said while the task of establishing forward services sector direction was not simple, there was a band of positive feeling on the horizon, with the sub-indices of orders and new business sitting on an expansionary 57.7-point position.
BNZ senior economist Doug Steel said the service sector had in general been a ''standout performer'' for some time, a narrative reinforced by May's results.
He said activity appeared particularly strong in May, with the sales index rising to its highest level since 2007, and noted strong new orders were encouraging for ongoing growth.
Business New Zealand chief executive Phil O'Reilly said that the key indicators; of activity/sales and new orders/business, pushed further into the 60-plus value range during May, indicating strong expansion.
