Yarra Trams has become the latest voice to hit out at Melbourne’s free tram zone, with the company revealing the scheme has added to delays on the light rail network.

In a submission to a parliamentary inquiry, the operator has argued against any push to expand the scheme to other parts of the city.

It said patronage in the CBD had surged by 30 per cent year on year after it was introduced and had led to more packed services that regular commuters struggled to squeeze on to.

Crowds of people getting on and off a tram in Bourke Street. Picture: Sarah MatrayThe amount of time that trams spent at many stops surged and Yarra Trams was forced to alter to timetable.

“The free tram zone has had a range of unintended or unplanned negative impacts, in particular overcrowding and slowing the tram services in the inner city,” the report reads.

“Expanding the free tram zone is likely to worsen some of these challenges, and reduces the budget available to address them.”

Yarra Trams also said the zone was undercutting the impact of spending on upgrades by the state government.

“There has been no improvement in passenger satisfaction in these areas despite more than 60 new large trams and a small number of additional platform stops,” it said.

The City of Melbourne called for further investigation into the scheme while a submission from the Melbourne Cricket Club encouraged extending the zone to the MCG.