Two MPs made the call on the second day of the Budget 2013 debate to freeze public transport fare increases until service levels improve.
Ms Lee Bee Wah (Nee Soon GRC) called on public transport operators to respond to the Government's call to raise productivity and innovate so as to reduce their operating costs, instead of passing them on to commuters.
Mr Liang Eng Hwa (Holland-Bukit Timah GRC) also said the Land Transport Authority and the operators have to "restore public confidence before we can even talk about fare increase".
A high-level committee to relook how fares for public bus and train services are set is looking into the affordability of fares, but Transport Minister Lui Tuck Yew has said it will be a challenge for the operators to do more without fare increases or government subsidies.
Mr Liang also suggested relying on private operators to speed up the ramping up of the public bus fleet, as they are entrepreneurial and resourceful.
He said: "If the two public transport operators are incapable of increasing the bus capacity fast enough, we should not waste time with them and quickly look to other private operators to do the job."