Many owners at Eunosville - one of only seven remaining such estates - were hoping to get the required 75 per cent vote last night.
But they did not, although there are still more votes coming in.
If they eventually get enough support and approval is given by HDB to privatise, an en bloc sale may be possible.
Eleven HUDC estates have already been privatised, said HDB.
A pro tem committee was set up in Eunosville in June to take charge of the privatisation process.
Chairman Suhaimi Mustapha, 54, a civil servant, said: 'Once the estate is privatised and we've formed our own management committee, then we'll think about that (en bloc sale).
'I think some of the residents want private estate status so that we can improve the surroundings ourselves.'
Some of the proposals include fencing up the estate, which is near Eunos MRT, employing security guards and building tennis courts.
Added Mr Mustapha: 'It's still too early to plan what to do. We'll do it step by step once we get the votes in.'
The privatisation process will take at least a year.
Each household is expected to pay about $25,000 for the process alone, he said.
The first privatisation exercise in this estate back in 1997 didn't succeed with only about 70 per cent yes votes, he added.
There are 10 blocks with a total of about 330 units in this estate.
All the units are about 1,700 sq ft and the estate is about 17 years old.
Housewife Madam Claire Quek, 45, said she voted for the privatisation to test the en bloc market.
Her family bought their unit for about $500,000 two years ago.
She said: 'If we can sell the estate, it'll be a bonus. If not, it doesn't matter because I like living here anyway.
'If it's privatised, at least we can fence up the estate and build amenities like a club-house.'
Accountant Terence Koh, 25, said his family didn't vote for the privatisation.
They've been living there for about 10 years.
He said: 'The location here is great and we've been living here for so long, so there's really no point in changing the status.
'And don't forget we'll have to bear all the costs of maintaining the estate once it's privatised. I don't think it'll be cheap.'
HDB said that once the estate is privatised, all the flat-owners will own their respective strata units, as well as the common property, as tenants-in-common.
A management corporation (MC) can then be formed.
Said an HDB spokesman: 'The MC will be responsible for the management and maintenance of the common property of the estate.
'It can then decide on the types of facilities, and the level of management and maintenance that is desired for the estate.'
HUDC flats were built by the now-defunct Housing and Urban Development Corporation for middle-income professionals in the 70s and 80s.
The ones that are privatised are run by the residents.
The rest are managed by town councils.
Laguna Park in Marine Parade was the most recent HUDC estate to be privatised, in July this year.
The estate has not been sold yet.
Farrer Court, an HUDC estate that went private in 2002, was sold for a record $1.3 billion to a CapitaLand-led consortium in June.
