A real estate insider claimed money from Mainland China was "vacuuming up" around 90 per cent of sales in some parts of Auckland in one month of this year alone and agents with close links back to China were behind that.
Asked about whether top agents had close connections back to China, Peter Thompson, Barfoot & Thompson director, said he did not know but the numbers were relatively low.
"I believe it's 5 to 10 per cent to foreign investors from China and that's roughly working off what we hear, but I have no proof and no statistics. I also think there are a number of people coming here from Australia and America."
Top agents often had teams of people they worked with, sometimes up to six, he said.
Big deals took a lot of work so back-up staff including administration personnel were needed, he said.
Labour's housing spokesman Phil Twyford said New Zealand citizens - regardless of their ethnic background - cannot compete with Auckland house buyers who live in China.
Figures he has released showed 39.5 per cent of Auckland houses sold from February and April by one big firm went to people with Chinese surnames, despite people of Chinese ethnicity making up only 9 per cent of the city's population.
In response to critics who have called Labour "racist", Twyford said if they disliked it they should reveal their own research and data on the issue.
But no other such comprehensive and up-to-date studies have been carried out to measure the number of people in China who are buying Auckland residential property, Twyford said.