The hot streak continues for Housing Board flats, with resale prices up again last month - the ninth straight month of increase - and the all-time high now within touching distance.

Buyers are being driven to the sector by a cocktail of factors, including rising values in the private home market, improving market sentiment amid easing restrictions, and delays in Build-To-Order (BTO) flats.

The result was a 0.8 per cent price rise from February to last month, noted flash data from real estate portal SRX out yesterday.

Resale prices are now 9.5 per cent above the level of March last year, and just 4.9 per cent below their peak in April 2013.

That peak may be passed by the second half of this year if the current rate of increase - about 1 per cent a month, based on SRX data - is maintained, noted Ms Christine Sun, OrangeTee & Tie's senior vice-president of research and analytics.

Mr Nicholas Mak, head of research and consultancy at ERA, said yesterday that prices are up due to robust demand from buyers who prefer the certainty of getting their flats in the resale market, to avoid the risk of construction delays for BTO homes.

Both Mr Mak and Ms Sun noted that cash over valuation (COV) - the amount buyers fork out if the sale price exceeds the HDB valuation - has been rising in recent months.

The average COV has increased in some locations, from $10,000 to $20,000, to $30,000 to $40,000, said Ms Sun, adding that rare and attractive units can command COV of more than $80,000 in some cases.

"Buyers are willing to pay a higher COV as they believe that the supply of choice units is limited, especially newer flats in mature estates," she said.

PropNex research and content head Wong Siew Ying said the sustained demand for resale flats has helped to support values, but as asking prices keep rising, so too would buyer resistance in the face of high COV.

This resistance could moderate the pace of price growth, she added.

Indeed, SRX's data yesterday noted that the pace of monthly increases has slowed of late - from 1.7 per cent in January to 1.4 per cent in February and 0.8 per cent last month.

The data also showed sales picking up after the Chinese New Year lull, with 2,448 flats changing hands last month, a 13.1 per cent increase over February. March sales were also 25.6 per cent higher than in the same month last year.

Four-room flats accounted for 43.3 per cent of sales, with five-room units next at 25.5 per cent, followed by three-room homes at 22.9 per cent, and executive apartments at 7 per cent.

Ms Sun expects sales volumes to pick up further with Singapore's economic recovery and construction delays for BTO flats.

At the highest end of the market, 17 resale flats were sold for at least $1 million, making up about 0.7 per cent of the total number of units resold.

The highest transacted resale price last month was the $1.22 million paid for a five-room Design, Build and Sell Scheme unit at Natura Loft in Bishan Street 24.

The highest transacted price in a non-mature estate was $910,000 for a five-room premium apartment loft unit at Treelodge@Punggol.

The 53 million-dollar resale flats sold in the first quarter were a 308 per cent increase over the 13 moved in the same period last year.

Mr Mak said HDB resale prices overall could increase 7 per cent to 10 per cent this year, due in part to the uncertainty and expected delays in the completion of new HDB homes.

On Wednesday, the Government announced that about 85 per cent of BTO projects are around six to nine months behind schedule due to construction delays caused by manpower shortages and supply chain disruptions.

This means that about 43,000 households will get the keys to their flats late.

Ms Wong said: "In the near term, we anticipate demand for resale flats to stay relatively healthy on the continued improvement in market sentiment, as well as the optimism arising from the projected rebound in the Singapore economy this year.

"That said, we remain watchful of policy risk and any potential impact on the HDB resale segment, as the authorities monitor price trends in the property market."