Ms Milne said Coromandel had been opening up as another suburb of Auckland and was a great option for those looking for a quieter lifestyle, with the ability to reach Auckland if needed.
Hawke's Bay, Wairarapa, Central Otago Lakes, Otago and the West Coast also recorded gains in sales volumes and median sales values.
Ms Milne said REINZ statistics across the board usually recorded less activity over the winter months but the difference in sales volumes in particular was considerable this year.
Tauranga Harcourts general manager Nigel Martin said the results were not surprising, given what they had experienced over the past few months.
Mr Martin said the firm had seen huge increases in activity.
"But I don't think anybody would have thought it increased quite so dramatically. The activity was not predicable but was not slowing down," he said.
"Doesn't seem to be slowing and now we are into spring and this is traditionally the busier time ...
"We have come through the winter months, which can be slower sometimes."
Eves and Bayleys Real Estate chief executive Ross Stanway said the REINZ results had not surprised him, either.
"This year there has been no slower period. There's been no winter slowdown in the real-estate market in the Bay, for sure. And there is no sign of the trend slowing down anytime soon.
"What we're talking about here is quite high volumes of sales in the Waikato and the Bay of Plenty, including in Tauranga, which is based on significantly greater base volumes numbers to start with, compared to the Coromandel and Northland region.
Mr Stanway said the 64 per cent rise was indicative of the continued high demand for homes. Also good news for Tauranga was the increase in the supply of new properties going on to the market.
Mr Stanway said Tauranga continued to be attractive to Aucklanders, who made up about 45-50 per cent of sales inquiries, and the large majority of the rest were locals.
Interest from Christchurch had slowed a little, he said.
Papamoa's new-home market is also proving a hit with a reported "stampede" of home buyers. Building companies report sales up 50 per cent on last year. Golden Sands sales and marketing manager Mark Day said sections could not be released fast enough.
House Sales Volumes
* June to August 2015 v June to August 2014
* Waikato up 96 per cent
* Coromandel up 91 per cent
* Northland up 74 per cent
* Bay of Plenty up 64 per cent
- REINZ data