Woodhouse said fewer residence approvals would be granted over the next two years and that the number of points required for residents will be raised to 160, instead of 140 points needed under the previous skilled migrant category.
In his letter, Ma points out how the real estate market in the area could be affected as a result of the new policy change.
"Our neighbourhood has been a popular choice for middle-class migrants from Asia. But as the new immigration policy comes in, there will be fewer Asian buyers in the market.
"Fewer buyers means less competition and this will almost certainly lead to a lower price for your property.''
The letter explains that up to thousands of potential buyers could be stopped from settling in New Zealand.
"With fewer rich overseas buyers in the market in the next two years, your property will possibly not bring you what it can today!''
The agent could not be reached for comment.
However, LJ Hooker Ponsonby franchise owner Steven Glucina backed Ma; saying although the letter may have been somewhat "over-dramatised'', it was a wake-up call for home owners who may be thinking of selling.
"Sometimes you need to shock people...to face reality. The whole property scheme is being fuelled by immigration, it's been fuelled by low interest rates and the availability of plenty of money.
"But those doors are closing now - the Government have indicated that they do want to cut back on numbers coming in.
"I guess it's probably a notice that went out just to wake people up and say: 'Hey, what would happen if we did have a correction?'
"Perhaps we should be thinking, maybe it's time to cash up, make a lot of money...and perhaps we could go to other areas of the country or other areas of Auckland and come out with a handsome capital gain - and have money left over and enjoy our lifestyle.''
NZ Chinese community leader Tony Wong, who has lived here for about 50 years, said moving to other parts of the country was not a popular move for Chinese.
Those who had lived here for years were based in Auckland. And new migrants usually chose Auckland for the sake of their children.
"[They think] about the kids' education. They don't want to go too far. Primary school is okay, but when they go to university, then that's the problem. They want to be close to what's in Auckland.''