Over the same timeframes investors or multiple property owners accounted for 30 per cent of the market, down from 32 per cent in 2014, while first-home buyers were at 15 per cent.
Meanwhile, movers who had sold a property within six months of purchasing another were 35 per cent of sales in 2015, down from 36 per cent, and had dropped further to 30 per cent in the first two months of 2016.
Senior research analyst Nick Goodall said demand from Auckland looked set to continue although reducing yields would slow it.
Sales to Aucklanders, either investing or moving into the area, picked up throughout 2015 as prices in Auckland continued to increase and the Government and Reserve Bank introduced a number of measures to try and slow that growth - mostly targeted at property investors. First-home buyers looking to enter the lower end of the market had seen significant competition from Auckland investors, he said. Auctions also became a more common method for selling property in Tauranga in 2015 - from less than 20 per cent previously to 60 per cent, he said.
"This is a sign of a strong market (likely influenced by Aucklanders, who are used to auctions) as it doesn't put a price on the property and lets the market decide.
"From our analysis we've seen auctions achieve on average a 4 per cent premium above properties selling via 'asking price'."
Auckland Property Investors Association vice president Peter Lewis said part of Tauranga's appeal was it was "a pretty nice place".
"Several years ago you could get 8 per cent interest and if you topped it up with the old pension you were lying in the sun and sipping your Bacardi on the beach. I think there has been a move for people to take their finances out of the bank and buy an asset and if you are a cash buyer that will give them an income they can live on in their old age."
Greg Purcell, franchise owner of Ray White Realty Focus in Mount Maunganui and Papamoa, said there was no question Auckland had a huge influence on the market, "it's like an invasion".
They were represented in significant numbers, he said.
"Everyone is making hay while the sun shines and I would say all things being equal we are just going to chug along for the foreseeable future."
The QV House Price Index revealed the average house values in March in Tauranga was $571,872 up from $466,378 in March 2015 and Mr Purcell said vendors had become ambitious in terms of expectations.
First National, Mount, Tauranga and Omokoroa owner Anton Jones said the halo effect had hit the city as Auckland became too expensive.
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"Aucklanders are coming down in droves and probably 50 per cent of our inquiry at least is from Auckland.
"I went to see staff at Omokoroa today and they have had a steady stream of Aucklanders walking in," Mr Jones said.
The boom had put Tauranga on the map as a destination, he said.
Tauranga Chamber of Commerce chief Stan Gregec said Tauranga could not grow without new blood and new investment: "We love Aucklanders but please don't all come at once".
"Do also bring the change you've got from selling up in Auckland and feel free to invest in local businesses or consider starting new ones.
"The fact that are we are attracting younger professional people who see a future here is a great sign that we are doing all the right things," Mr Gregec said.
Priority One projects manager Annie Hill said if Auckland investors were adding to the rental property pool which was great news for the city.
