Its president Daniel Bowen said extra off-peak services would help spread the peak load, without losing revenue, by giving people a free ride.

He said some people travelled during peak hours because they faced longer waits and travelling times during off-peak periods.

"You don't need to bribe people into moving their trips outside peak hour. It's more important to get more services running. Those things can be fixed- they don't require more trains, they just require smarter timetabling."

However, Eastern Transport Coalition chairwoman Samantha Dunn said an increase in the early-bird period would be good for those in the outer areas.

"The ETC would like to see free travel periods extended to trams and buses as well."

RACV chief engineer of traffic and transport Peter Daly said he would support the plan if it was proven to reduce congestion on the roads.

He didn't believe the early-travel bonus alone would be enough to lure people onto the trains. Improved timetables and more frequent trains would also need to be reassessed, he said.

"If you change the number of people travelling on the roads by as little as 2 or 3per cent, there would be a noticeable difference."

Victorian Employers' Chamber of Commerce and Industry spokesman Chris James said the system had worked well "at the margins" but did not support an extended scheme because of "revenue leakage".

"The free before-7am system gives commuters a choice. It also suits businesses that open their doors at 7am or before. It will not solve our public transport problems, nor is it designed to."