According to Singapore's telecommunications sector regulator Infocomm Development Authority (IDA), the penetration rate for residential lines, which had held at about 95 per cent of households from 2006 to mid-2008, has come down to 93 per cent.

Consulting firm Gartner's research director for carrier operations and strategies Foong King Yew believes that most of those who have ditched their fixed phone lines are probably from the younger working crowd.

These users do not spend much time at home, and even when they are at home, he said, 'they are so used to their mobile phones that they will make calls from (them) even if the landline is next to them'.

A SingTel spokesman agreed with Mr Foong's assessment.

SingTel, she said, has seen 'a convergence between fixed and mobile services ...as customers, especially the young and tech-savvy, are increasingly on the move and are demanding to be connected wherever, whenever.'

Just five years ago, when the IDA first released data on residential phone line numbers, the penetration rate was 102.4 per cent.

That was because many homes had two phone lines - one for voice calls and the other to dial up the Internet, said Mr Foong.

But as new technologies such as broadband Internet modems appeared and the penetration rate of mobile phones rose, the need for so many fixed phone lines faded, leading many homes to cut back on the number of lines they had, said Mr Foong.

He believes SingTel's October 2008 price hike for fixed lines may also have played a part in the decline.

Read the full report in Thursday's edition of The Straits Times.