OPERATORS of Melbourne's bike hire scheme have ordered thousands of helmets amid predictions bargain-hunting cyclists will snap up the state government-subsidised headwear.

RACV has ordered 5000 helmets designed to match the blue hire bikes as part of a trial to make the scheme more accessible to casual users.

As part of the trial, announced earlier this month, helmets can be purchased from vending machines at Melbourne University and Southern Cross Station and from selected 7-Eleven stores for just $5. If users return the helmets – made from polystyrene and thermoplastic – they will get $3 back and the helmet will be cleaned and disinfected before being resold.

Bicycle Victoria spokesman Garry Brennan suggested the "Melbourne" helmets could become tourist souvenirs and even fashion statements.

Mr Brennan said it would be an interesting experiment to see if the availability of helmets improved the bikes' popularity. He said the low price of the helmets, which cost the government about $13 each, did not mean any reduction in safety.

"Australia has the toughest helmet standards in the world, and these helmets exceed those standards," Mr Brennan said.

BSC Bikes in Elizabeth Street store manager Travis Johnston said people wanting to borrow bikes from the rank outside his store had been put off by the need for a helmet.

The cheapest helmet on sale at the store is $40, and top-of-the-range helmets can cost 10 times that. He doubted serious cyclists would be tempted by the cheap helmets. "It's a totally different market."

Melbourne Bike Share has been used for more than 20,700 trips.