Just 793 first-home buyers took advantage of the revised NSW first-home owners' grant in December last year.
There were 4,233 recipients in the prior December.
The numbers were also down in November last year with 1,763 recipients.
There had been a 2,920 monthly average over the past two financial years.
The December figure was the lowest since the first-home buyers' grant was introduced in 2000 as a measure to offset the introduction of the GST.Click to enlarge
However the NSW opposition has accused the NSW government of "locking young people out of the housing market after the state recorded the lowest numbers in two decades".
The acting opposition leader Linda Burney blamed the drop on the government's decision to scrap the all encompassing $7,000 first-home owner grant along with stamp duty exemptions worth up to $17,990 for first-home buyers purchasing existing homes.
Only buyers of new apartments and houses now qualify for the grant. The $15,000 first-home owner grant (new homes) started in October last year. The grant will reduce to $10,000 in January 2014.
The data was confirmed by the Australian Bureau of Statistics (ABS) showing only 1,383 loans for first-home buyers were approved in November last year.
This is the lowest ABS figure since February 1992, Burney says.
"These figures show Barry O'Farrell has locked first home buyers out of the property market," she said in a statement on Tuesday.
"The premier's decision to dump first-home buyer grants and stamp duty exemptions has been nothing short of devastating for young people trying to buy their first home."
Burney said first-home buyers buying an existing $500,000 home in November 2012 were forced to pay $24,990 more than they would have a year earlier.
"The O'Farrell government has created the worst environment in 20 years for first home buyers trying to enter the housing market," she said.
Acting Treasurer Greg Pearce told Fairfax Media the fall was due to a period of transition to the new grant.
"This was a difficult decision. However, we believe this is necessary to make buying a new home or apartment relatively more attractive than buying an existing dwelling."
Murray pointed out that Queensland, which made similar policy changes also taking effect in October, suffered a 33% fall in loans taken out by first-home buyers in November.
"I think it's too early to tell what impact the NSW grant is having," he said. "Clearly, during the periods of transition you get some strange things happening."
The Housing Industry Association economist Geordan Murray also said it was appropriate to wait for a few more months' data before drawing conclusions.
Westmead and Liverpool, with about 550 recipients, were the suburbs with the highest uptake during 2012.