Public transport fare increases in Singapore over the last few years have been lower than cities such as Hong Kong, London and New York, said Transport Minister Lui Tuck Yew.

Responding to questions from MPs on transport fare hikes over the past few years, Mr Lui told the House that fares here are generally comparable and typically lower than those cities mentioned.

He said: "The Government is fully committed to keeping public transport fares affordable. Indeed, we want to carefully study this issue in greater detail for different income levels and various special groups that may be more vulnerable and will need special help should fares have to be raised."

Mr Lui said public transport fares have been adjusted in small amounts seven times from 2003 to 2012 by the Public Transport Council (PTC).

From 2006 to 2011, fares increased cumulatively by 0.3 per cent, while diesel prices went up by about 55 per cent and national wages by more than 25 per cent over the same period.

This has caused a significant shortfall between fare increases and operating cost increases, and put downward pressure on wages for public transport employees, said Mr Lui. Given worsening bus industry financials, he expects it will be a challenge for the transport operators to "do more without fare increases or Government subsidy".