SkyBus fares between Melbourne Airport and the CBD will rise on Wednesday, extending the margin by which Melbourne has Australia's priciest city-to-airport public transport, even as major roadworks make the journey more time consuming.

The one dollar fare rise will increase the cost of a one-way SkyBus trip to $19, or for $36 to $38 return. It is the service's first price increase since December 2013.

Passengers have been warned of the impending, 5.5 per cent price rise at SkyBus departure points, but there has been no mention of it on the SkyBus website.

As a sweetener, the cost of a family ticket will be reduced..