Melbourne Airport is on track to become the busiest airport in the world without a rail link within 10 years, risking costly gridlock on the Tullamarine Freeway, airport boss Chris Woodruff has warned.

In a forceful broadside aimed at the Andrews government, Mr Woodruff lamented that building a passenger railway to Tullamarine had fallen off the political agenda since November's election, despite rapid growth in visitor numbers, particularly from Asia.

The construction of Terminal 4 at Melbourne Airport. Credit:Jason South

"We need a rail link to the airport," Mr Woodruff said. "It's a compelling argument. It was on the last government's agenda; it doesn't seem to be a high priority on this government's agenda."

The airport chief, who is due to step down this year, told an audience at a Trans-Tasman Business Circle discussion panel in Melbourne that visitor numbers are on track to grow to more than 45 million people a year within a decade.