The largely unstaffed 24-hour gym is the latest trend turning the fitness industry on its head.

Three have already set up in Launceston with another three to come.

Few staff, low fees, no contracts and the ability to workout around the clock is proving a winner among gym-goers.

But are the gyms safe?

Unsurprisingly owners say ``yes'', while competitors who are watching business run out the door say ``no''.

Fitness Australia, the industry's peak body, said it was satisfied with the safety measures the 24-hour gyms had in place - 24-hour CCTV, panic buttons that can be worn by customers alerting police and paramedics, and onsite medical equipment.

But some remain unconvinced believing it is just a matter of time before something goes wrong.

One Launceston operator compared it to ``going into a barber and asking for some scissors to cut your own hair''.

But 24-hour gym owner and former Liberal party leader Bob Cheek said it was just as safe if not more so than conventional gyms. ``We spent a heck of a lot of time on this. We haven't had one problem at all and insurance companies reckon we're better scrutinised than gyms which have people on the floor at all times,'' Mr Cheek said.

What if something goes terribly wrong for somebody working out by themselves?

``If anybody's going to have a heart attack on the floor, wherever they are it's going to be difficult. If anybody had a health problem they shouldn't be working out anyway,'' he said.

The growth of Mr Cheek's Tasmanian-owned Zap Fitness is staggering.

In the past three years Zap has opened 14 outlets here and one in Victoria.

It has another three planned for Launceston and another five for Victoria, with the goal to run a network of 20 gyms in Tasmania.

Mr Cheek owns a ``full service'' gym in Hobart but is convinced the future lies in the new stripped down model where customers don't pay for things they don't use. He discovered the gyms while visiting the US and said their resilience to the global financial crisis impressed him.

``We've taken customers away from conventional gyms, there is not a doubt about that, but we're offering a model people want,'' he said.

Fitness Australia agreed saying it was ``the consumer driving these type of models because of their time efficiency and cost efficiency''.

``It's something we've all had to get used to in the industry, it's not going to go away and it's an important part of the industry,'' Fitness Australia's chief executive Lauretta Stace said.

She said they were ``very actively managed for risk''.