The resale prices of HDB flats last month fell by 0.3 per cent from December, and stood 0.1 per cent lower than in January last year.
From their peak in April 2013, prices have fallen by 11.2 per cent, according to SRX Property.
Resale prices for three-room and four-room flats fell by 0.6 per cent and 0.5 per cent respectively.
Meanwhile, prices for five-room and executive units rose by 0.4 per cent and 0.9 per cent respectively.
HDB resale prices in mature estates fell by 0.7 per cent, while those elsewhere stayed the same.
The volume of resale units has also fallen. In January, 1,174 flats were sold, down by 13.9 per cent from 1,364 units in December. Year on year, this was a drop of 8.9 per cent.
The volume of resale units peaked at 3,649 units in May 2010.
Overall, buyers paid $3,000 less than the estimated market value last month.
In towns with more than 10 resale transactions, Geylang reported the highest above-market prices, as buyers there forked out $5,500 more. Tampines home prices were second highest, with a price difference of $4,000.
Meanwhile, Punggol recorded the lowest below-market prices, with buyers paying $8,500 below value, followed by Yishun and Toa Payoh, at $8,000.