It's no secret the Hobart rental market is tough for tenants at the moment with a vacancy rate of just 0.3 per cent, the lowest of all Australian capital cities.

Competition for each property is tight with stories of people paying up to 70 per cent of their income on rent, while the waiting list for public housing has blown out to more than 3,000.

Interstate stories about mobile apps and websites which allow people to make bids for rental properties has prompted an online petition calling for them to be banned.

Ben Bartl from the Tenants' Union of Tasmania said openly bidding for rentals or asking for a rental range was illegal in Tasmania.

"In Tasmania, all rental properties have to be offered for rent at a fixed price," he said.

"Consumer Affairs and Fair Trading would come down on such apps like a tonne of bricks.

"It's against the law to have a range or in this situation an eBay-type model where the rents can be incrementally increased."

Big rent increases common

While rent bidding is not legal in Tasmania, there is no limit on how much rent can be increased by the landlord when a lease is up for renewal.

Mr Bartl said calls to the union this year were mostly about such increases, as well as evictions.

"We've taken on more cases [this year]," he said.

"There seems to be more landlords who are evicting their tenants; in some cases it is because they want to put the property onto the short-term rental accommodation market.

"Unfortunately without regulation there's not much we can do."

Are requests for credit and police checks legal?

Because of tight competition, real estate agents and landlords are getting away with asking potential tenants for forms and information they cannot legally require.

Meredith Barton, principal solicitor with the union, said while most applications asked for a credit check to be provided, it was not a legal requirement.

"The agents aren't allowed to seek that credit check themselves; they can't go to Tas Collections and ask for a credit check on a tenant," she said.

"The way they're getting around that is they're getting the tenant to provide that credit check."

You can get a free copy of your credit check once a year with a processing time of 10 days, otherwise a fee of $20 is charged.

Ms Barton said some agents and landlords were asking applicants to provide a police or criminal check, which costs around $45.

"There's no real criminal history that should allow them to refuse the tenancy," she said.

While an applicant was within their rights to refuse to provide a credit or police check, Ms Barton said they knew not doing so could make securing a property harder.

"We say you don't have to provide it," Ms Barton said.

"But if 30 people apply, 29 provide it and you're the one that doesn't, you're the one on the bottom of the list."

Call for standard form across the state

Mr Bartl said the union had been campaigning for a standard statewide rental application form to stop unneeded and potentially discriminatory questions being asked of applicants.

"In our view there needs to be a standard application form.

"There's lots of questions that we say don't need to be asked.

"Some real estate agents will ask for three months' worth of your bank statements; we say that's an intrusive question ... there's no requirement to ask a question like that."

Mr Bartl said the next Tasmanian government would need to act on housing and rental issues affecting the state.

If you have a question or concern about renting in Tasmania, you can contact the Tenants' Union of Tasmania on 1300 652 641 or visit its Facebook page.