Melbourne's blue hire bikes could soon carry advertising stickers to help offset the costs of running the city's bike hire program even though usage is up on last year.

VicRoads, which manages Melbourne Bike Share, has confirmed it is looking at putting stickers on the 500 bikes at docking stations dotted across the CBD and inner suburbs.

"VicRoads is investigating options for advertising on the Melbourne Bike Share bicycles and helmets," Patricia Liew, VicRoads' metro north west regional manager, said.

The bike share scheme was launched in winter 2010 and running it and subsidising helmets costs an estimated $2 million every year.

VicRoads figures show usage of the bikes increased by about 30 per cent in the year to June.

There were more than 16,000 rentals in January, compared with almost 13,000 in January 2011.

The figures dropped over winter, with 9617 rentals in July, although that was an increase on the 7982 bikes that were hired in July 2011.