Restaurateur Mickey Gubas, who holds the lease to run a restaurant and cafe in the building, stopped paying rent two years ago and took Telstra to the ACT Supreme Court over the alleged faulty tower.

He claimed the problems had cost his business hundreds of thousands of dollars.

But a Telstra spokesman said all facilities at the tower were safe and in working order and it would be inappropriate to comment on the legal proceedings.

A 2011 building inspection report by Washington Brown, and paid for by Mr Gubas, found ''the poor condition of the building services at this location have potential to seriously impact the health and safety of the occupants and visitors, as well as significantly hampering the economic effectiveness of the restaurant''.

The report also found the revolving floor controls were ''in very poor condition'' and ''not electrically safe'', while the airconditioning was ''past the end of its design life cycle and should be replaced''. The copper sewer pipe had ''failed in this area several times''.

In his summary, consultant Peter Caruso said the building's services, such as pipes and airconditioning, were in ''poor condition and reflective of their age'', and ''with few exceptions the mechanical services at this location are well past the end of their economic life and in very poor condition''.

Mr Gubas said lifts broke down, drainage in the kitchen was frequently blocked and there were often power outages.

''I've had chefs stuck in lifts during service, the kitchen floods, the roof leaks and all our perishable goods have been ruined by power outages,'' Mr Gubas said.

''When I signed the lease I was told there were 300,000 plus visitors to the tower each year. That has dropped to about 150,000.''

And he said refurbishments to the tower last year were cosmetic and staff had been lucky to escape injury. ''It didn't fix the lifts or the airconditioning or the internet,'' he said. ''The flooding in the basement kitchen caused our oven to short circuit and blow up. Fortunately no one was hurt, it could have been a disaster.''

Telstra have a counter-claim against Mr Gubas for unpaid rent.

''What we can say is that we would only take this type of action as a last resort and after we had exhausted all attempts at mediation,'' a Telstra spokesman said.

''Telstra has engaged professional property managers to ensure the building is well maintained and whenever faults have been reported, Telstra has promptly arranged for repairs and maintenance whenever necessary … In regards to the quality of the facilities at Black Mountain Tower, all amenities are safe and in working order.''

In July, Chief Minister Katy Gallagher wrote to the area manager of Telstra, Chris Taylor, and raised concerns about exhibits and the unkempt appearance of public areas at the tower.

While the ACT government does not own or operate the tower, all Crown leases contain standard provisions relating to maintenance and repair of properties.

''The government can act to enforce those provisions where it is satisfied that public health or safety concerns warrant intervention,'' a spokesman from the Environment and Sustainable Development Directorate said.

''The government has no evidence to indicate that enforcement action is warranted.''

Telstra and Mr Gubas are due back in the ACT Supreme Court on February 20.