House prices dropped on Auckland's Waiheke Island last year for the first time in six years, says Waiheke Real Estate manager and salesperson Paul Brisbane.

The median house price on the island fell by 1.6 per cent in the year to November 2017, Brisbane said.

In November, the median house price on Waiheke was $885,000, while in Auckland the median was $880,000, he said.

Waiheke's median house price peaked at $1,037,500 in June 2017 and has been falling every month since, Brisbane said.

In 2015, the government introduced the bright-line test, charging tax on profits from investment properties sold within two years of buying.

"A lot of investors have been pulling out of the market," Brisbane said.

The new government has indicated plans to introduce new standards for rental homes, prompting some landlords to sell, he said.

The property market slowed down in the lead-up to the general election in September last year.

Although this happens every election year, the delay in forming a government further dampened the market, he said.

"We had about half the number of sales for the six months before November and it slipped to more of a buyers' market."

The number of sales began to return to normal in November, with the biggest leap in sales numbers between October and November for six years, Brisbane said.

While the number of lower priced properties being sold has increased, plenty of million dollar mansions have also changed hands.

In the past year on Waiheke, four per cent of properties sold for more than $4 million. This has increased from two per cent in 2016.

The highest price paid for a residential property on Waiheke last year was $8.2 million for two houses on a beachfront property at Palm Beach, Brisbane said.

A house will soon come onto the market at Palm Beach that is expected to fetch more than $10 million.

The median house price was $470,000 at the end of 2007 and many houses have doubled in value over the past five years, Brisbane said.

Cooper and Co Real Estate managing director Martin Cooper said the number of properties sold on Waiheke dropped by 36 per cent from 354 in 2016 to 226 in 2017.

The median selling price for all properties on islands in the Hauraki Gulf in the year to November 2017 was $919,500, up 3.9 per cent from $885,000 in 2016, Cooper said.

While some properties are selling fast for high prices, some have overestimated the value of their properties based on Auckland Council's recently increased valuations, he said.

"These homes are still for sale because buyers won't pay the prices being asked.

"Properties with great location and sea view are still achieving some excessive prices, as buyers with ample funds simply want their special slice of Waiheke and are prepared to pay for it," Cooper said.

Waiheke Bayleys principal Mary Curnow said while prices have stopped "steaming ahead", waterfront properties and those close to the ferry are still in demand.

"Oneroa is really popular and often the further away you get from the ferry, the more the prices level out," Curnow said.

Both Brisbane and Curnow noted the shortage of rental properties available on the island, particularly over the summer.

"People can't find homes and there are lots of people applying for the same rental property," Curnow said.