Harcourts managing director Nigel Martin said Aucklanders were still making up 50 per cent of the buyer pool.
December 2015 was the busiest month his franchise had ever had, he said.
"It's not backing off. As an industry our stock levels got pretty low at the end of winter last year and they are back down to that same level now. Maybe a little bit lower at the moment."
Mr Martin said more housing stock would come on over the next few weeks with people coming off summer holidays. He predicted this year's market would be strong.
"Low levels of listings, higher demand. Obviously this is going to put pressure on price."
Greg Purcell, franchise owner of Ray White Realty Focus in Mount Maunganui and Papamoa, said the current growth was built on the exodus out of Auckland.
"There is no question, if that slows down, we will slow down."
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Mr Purcell said when the bright-line regime laws came in last year there was a brief slow down but since then sales had picked back up.
He said it was hard for buyers to know where the apex of house values were, with supply and demand driving the market.
Eves and Bayleys Real Estate chief executive Ross Stanway said the year-on-year increases had been building over the past 12 months with a "very rapid increase over the past six months of 2015".
"I think particularly, but not solely, in that Auckland market a lot of people are looking further afield and looking at the sort of lifestyle and property prices and the opportunities that they have there."
Mr Stanway said more people were also beginning to appreciate the potential value for money in the Tauranga and Western Bay of Plenty areas.