Auckland iwi have been invited to develop a 9.5ha site in Massey East but they have not yet responded.
Four sites with a total area of 30ha are ready to be offered to developers. These sites can fit up to 600 homes. One of them, in Hobsonville, is yet to be cleared for development.
Dr Smith said another 20 sites with a total area of 100ha had been "identified as having potential ... but more work is required to confirm their suitability for the programme".
Of the 250 developers that expressed an interest, 19 have applied to be involved in the scheme and 15 approved.
Labour's housing spokesman Phil Twyford said the scheme appeared to have shrunk to a fifth of its original size.
"On Budget day, the Minister was crowing about the 500ha of Crown-owned land that would turned into affordable housing," he said.
"Now he has been forced to admit that only around 100 hectares have the potential to be developed."
Dr Smith said the programme was progressing more slowly than hoped, mainly because of a legal challenge by iwi who had first right of refusal on some land. But he remained confident 500ha of land would be found.
"We are still working to the original plan and there are some very large sites that are being explored that would make substantive progress towards those sorts of numbers," he said.
The minister was also encouraged by recent growth in housing supply in Auckland.
Statistics New Zealand revealed yesterday that 2831 dwelling consents were issued in November - the most in a month since March 2005. Of those, 966 were in Auckland.
This was just short of the 1000 new homes a month required to meet Auckland's housing shortage.
Auckland housing plan
Proposed
• 500 hectares of surplus land in Auckland freed up for housing development.
• Potential for up to 10,000 new homes within three years.
• First agreements to be signed in October.
Progress
• No agreements signed.
• Four sites ready to be offered to iwi/developers, with potential for 600 homes:
Moire Rd, Massey East
(9.5ha, 200 homes)
Wiri Station Road, Manukau
(1.4ha, 60 homes)
New North Rd, Avondale
(0.37ha, 60 homes)
Brigham Creek Rd, Hobsonville
(17.9ha, 270 homes)
• 20 other sites being considered with a combined area of 100ha.