Martine Letts, who represents a committee of 150 organisations in Greater Melbourne, said she had not heard of an alternative solution from the State Government that would facilitate fast rail from the regions.
“A tunnel from Southern Cross to Sunshine would provide a solution that’s long-lasting and strategic,” she said.
“This is a once-in-a-generation opportunity, and it's very important to get it right.”
Ms Letts said faster rail times would encourage people to live outside the metropolitan area, which would encourage sustainable population growth in Melbourne.
“(Fast rail) would build a better, productive ecosystem beyond Melbourne,” she said.
“We are keen to hear from the government about any of the alternatives that they might have to achieve that outcome.”
Greater Shepparton City Council chief executive Peter Harriott said council had written to State and Federal governments “consistently” for better rail services in Shepparton, and had written to the Deputy Prime Minister and the Premier to support the airport link tunnel.
“Council believes (the tunnel) is a project needed for the long-term benefit and growth of the regions,” he said.
Mr Harriott said a link from the airport to Shepparton would be an advantage, and would require a tunnel for trains to avoid congestion.
A Department of Transport spokesperson said it was working closely with the Federal Government on all options for airport rail, and did not indicate when final plans would be announced.
The Shepparton rail line is currently undergoing a $350 million upgrade, which will lead to an extra nine train services per day.
MORE STORIES ON THE MELBOURNE AIRPORT RAIL LINK
Fast rail ‘impossible’ for Shepparton if dedicated airport tunnel is ditched
AirRail tunnel could provide fast access to CBD for Shepparton travellers
Hopes Shepparton will benefit from airport rail link