A rail line to Melbourne airport is not one of the Andrews government's priorities but widening the Tullamarine Freeway is, says Roads Minister Luke Donnellan.

Speaking at a media conference on Sunday, to announce $300 million worth of widening works starting on the Metropolitan Ring Road, Mr Donnellan was asked about the need for an airport rail line.

The questioning came after The Sunday Age revealed that a group of advisers set up by the Andrews government secretly reconsidered a rail link to the airport as one of several "strategic investments" to boost Victoria's tourism prospects.

There are almost 34 million passengers a year passing through Melbourne Airport – up from 25 million six years ago.