But a Transport for NSW spokesman said the South Coast line will remain untouched.

Last week, a Transport for NSW/Sydney Trains report into the resilience of the rail network recommended moving off-peak trains with low patronage to peak periods, where they would provide “extra capacity for incident recovery during peak service periods”.

Some afternoon services leaving Sydney on the South Coast line have only four carriages and commuters have claimed they are overcrowded.

TfNSW has said trains on the South Coast line during the afternoon peak all had eight carriages.

Wollongong MP Paul Scully has raised the spectre that carriages on South Coast trains may be moved to Sydney lines.

“These are the questions and the uncertainty that commuters are facing at the moment,” Mr Scully said.

“We just don’t know what the actual plans are. We just don’t know how the government intends to handle the question of what services will remain and what services won’t.

“I’m hoping the government won’t use this as an excuse to further diminish services on the South Coast line.”

The TfNSW spokesman said it was not unusual to carry out reviews after bringing in a new timetable, which would include looking for opportunities to make minor adjustments to reallocate resources from the off peak times to peak hours.

“NSW TrainLink South Coast Line services will not be affected by the proposed changes,” he said.