What will be Adelaide's tallest building has been approved by the State Commission Assessment Panel, adding 38 levels of floor space to a CBD that already has 220,000 square metres of unoccupied commercial space in untenanted buildings.

The building will be erected on the site of the Adelaide Metro Info Centre at the corner of King William and Currie streets by Equinox Property Group, whose plans include 266 hotel suites, 78 residential apartments and a restaurant and bar.

At 132.4 metres, it will be 40 centimetres taller than Westpac House, giving it bragging rights over the city's relatively low skyline.

But others are pushing to see Adelaide's many untenanted commercial buildings — some of which have been languishing for decades — repurposed for residential purposes in a scheme similar to Melbourne's achievement of the mid-1990s.

Daniel Gannon, executive director of Property Council of Australia SA, said current empty floorspace was equivalent to 10 Adelaide Oval playing surfaces and about 50 per cent higher than the historic average.

"Adelaide right now has a challenge around demand rather than supply," he said.

"Having said that, it shouldn't be knocking back new stock into the market because new stock helps shape the city and is a sign of maturing capital.

"That means our policy makers need to work harder to attract more tenants, more business owners and more risk takers to Adelaide to take up some of this future floor space."

Mr Gannon said the refurbishment of older buildings had been constricted unrealistically by red tape and building code impediments.

He pointed to former Victorian premier Jeff Kennett's Postcode 3000 strategy of the mid-1990s, which aimed to convert unused office towers and buildings into residential and student accommodation and bolster Melbourne CBD's population.

The Victorian government attributed it to the emergence of Melbourne's bars, cafes, laneway culture and supermarkets, and believes it turned it into a "radically improved city".

"Postcode 3000 does present a really interesting case study for Adelaide right now," Mr Gannon said.

"The challenge for the State Government, but also the City of Adelaide, is to think very sensibly and very carefully about what they might want to do with policy, to incentivise building owners to repurpose some of their stock in a realistic way."

New tram to service empty buildings

The owner of Michael Treloar Antiquarian Booksellers has been watching the installation of the new East End tramline along North Terrace directly outside his store since August last year.

A new stop will service the war memorial, the state library, museum, art gallery and University of Adelaide on its north side, but on the south side will arrive at a pocket of buildings that have largely been empty for up to 20 years.

The first top on Adelaide's East End tramline will service a largely empty group of buildings on the south side of the terrace. ( ABC Radio Adelaide: Malcolm Sutton )

Mr Treloar said Adelaide was a unique city for all the wrong reasons, by having a strip of buildings vacant along its most well-populated and spectacular cultural precinct, which is also just a stone's throw from the Riverbank and Adelaide Oval precincts.

"I cannot see where anywhere else on Earth a spot like this would not be something you would die to be in," he said.

"It seems to me there are relatively few owners of a relatively large number of properties on the market."

He said the owners needed incentives to tenant their buildings, perhaps even under the threat of being forced to put a CBD property back onto the market after a period of time if they don't utilise the space.

"Until somebody such as the council or the State Government causes a revolution in owners being made responsible for the buildings they own, then we'll continue to get this situation of empty buildings," Mr Treloar said.

This includes an untenanted, multi-storey building around the corner on Gawler Place that he considers to be the "biggest rat house in the city".

"Until it is more profitable for an owner to have tenants at affordable rents than it is for the owner to keep those buildings empty for decades, then this will continue ad infinitum," Mr Treloar said.

Michael Treloar says owners need incentives to tenant their buildings. ( ABC Radio Adelaide: Malcolm Sutton )

Government to 'cut red tape'

Planning Minister Stephan Knoll said the state's planning system was "currently going through a once-in-a-lifetime reform" that aimed, in part, to reduce bureaucracy and red tape.

He said the Government, which was elected in March, had a plan to make it easier for many CBD buildings to be rejuvenated.

"Under the provisions of the current building code, upgrading and reactivating existing buildings is often cost-prohibitive as such development has to comply with the same requirements as if it is being newly constructed," Mr Knoll said.

"Our initiative will cut the red-tape burden associated with giving a new purpose to an existing office building."

Mr Treloar welcomed the shift in strategy, but warned a plan like Victoria's Postcode 3000 would have been more successful in Melbourne because there was a higher number of building owners, rather than the concentrated few in Adelaide.

The CBD's re-opened Electra House is an example of a heritage building being repurposed — in this case as a bar. ( ABC Radio Adelaide )

Can a Postcode 5000 work in Adelaide?

Mr Kennett said Postcode 3000 was about putting the policy and "fundamentals" in place to encourage people to invest in both new buildings and reconditioning old ones.

He said it took off from 1997 and, since then, the city had turned around from being a "stagnated" population to one that was constantly in demand of residential spaces.

"Yes, I think it could happen in Adelaide as well, and I know [SA] Premier Steven Marshall is trying to put a commercial flavour into the way government is managed at assessing opportunities," Mr Kennett said.

"But I think the biggest issue for Adelaide is the question of what the city stands for and what is going to be the genesis of future growth that is sustainable."

Long-term empty or near-empty buildings have prime location on North Terrace. ( ABC Radio Adelaide: Malcolm Sutton )

Despite Melbourne's turnaround, he said there was an increasing number of empty shop spaces due to "tightening of wallets or the competition of online shopping", which could have an effect on occupation.

"In Adelaide, I think the catalyst for growth should be in education, not only in universities, but in the broader community, and that would bring more life to the city.

"I think a discussion about the two universities merging together is without a doubt the most sensible thing in a long time.

"It will get critical mass, in terms of education, and have one University of Adelaide that could have an international face to market, which could bring some of the best lecturers and professors from around the world to attract students to Adelaide for short and long courses."

Both chancellors of the University of Adelaide and University of SA are undertaking a six-month collaboration period to produce a report that determines the viability of a merger.

The Government is also building a $100 million Adelaide Botanic High School just off North Terrace on Frome Road, which is expected to be opened in 2019 for 1,250 students from inner-city suburbs.