It will check any rules are” encouraging or allowing” people to speculate on HDB flats, said National Development Minister Mah Bow Tan.

At the meantime, it will step up efforts to make sure people do not get away with abusing the system.

Under HDB rules, citizens and permanent residents who buy resale flats without housing grants or HDB loans must live in the flat for at least one year before selling, or at least three years before renting out the entire flat.

Speaking on the sidelines of a housing conference hosted by the HDB on 27 January, Mr Mah said these claims were worth checking and he wanted to ensure that such factors were not inflating the market artificially.

He said it would not do if buyers were buying flats because they hoped to make money through flipping or selling the flats later on, or by renting them out without living in them.

He did not know how prevalent such practices were but added that “anecdotally, you do hear cases, so I want to make sure that this is not happening”.

The HDB’s findings will be out in a couple of months, he said.

Mr Mah acknowledged that recent housing data had raised fresh concerns about high resale flat prices.

Mr Mah said the Government did not wish to meddle in the resale market, and COV payment were part and parcel of the market.

“If you‘re a buyer, you feel anxious, understandably you want prices to be low.  But, if you’re a seller, you want prices to be high. It’s not possible for the Government to set the resale prices,” he said.

“The buyer might be happy today, but tomorrow he’s a seller and if we set the prices of what he wants to sell, he’ll be unhappy.

“Let the prices be set by willing buyers and willing sellers. We, don’t , and should not, interfere in the resale market.”

Mr Mah also downplayed the impact of permanent residents on the resale market.

“Our numbers show that the PRs are buying about 20 per cent, or one in five flats sold. So yes, they do have some impact, but they don’t have such a great impact,” he said.

Asked if PRs should be restricted from buying in the resale market, Mr Mah said that was not the right thing to do.

PRs also need a place to live, he said, and the solution was to make a clear distinction between Singaporeans and PRs in terms of the grants they get.