The news comes after the developers announced on Monday that the $1 billion mixed-use precinct would be accelerated to be built in just over three years instead of the 10 years initially planned.

The financing agreement with Goldman Sachs will see stages one and two of the precinct, including the commercial, retail and hospitality accommodation, completed by 2021.

Geocon director of commercial sales and leasing Mark Nicholls said the commercial hub, Urban at Republic, would set the benchmark for placemaking in Canberra.

He said the retail and commercial space would be a mix of food and drink outlets, specialty retail, and professional such as solicitors and medical practitioners.

Geocon says the development would "house an anchor supermarket", although the planning directorate, in its 2016 notice of approval, described it as a "market hall".

The decision describes a market hall as having "multiple vendors, which provides for a different shopping experience and layout than a standard supermarket", and said it would not detract from the main Belconnen shops and town centre. The government said the market hall would be 662 square metres, and at that size met the planning criteria.

The Belconnen centre masterplan recommended "a convenience supermarket" on the eastern side of the town centre and the draft precinct code allowed two locations with 1500 square metres altogether, the directorate said.

Mr Nicholls said the development "will have the look and feel of Melbourne's inner-city cafe culture crossed with London high street and a Parisian plaza" .

The hub will be at the axis between the Belconnen town centre and the University of Canberra, Lake Ginninderra and the government office precinct, which Mr Nicholls said was a dynamic environment at all times of the day with thousands of students, shoppers and workers around.

"We have already agreed sales and leases on more than 3000 square metres of the commercial space in the precinct and continue to receive enquiry on a daily basis," he said.

"Business operators are drawn to being located on the doorstep of more than 1200 apartments and a 135-room hotel."

High Society, which will be the Republic precinct's - and Canberra's - tallest building at 113 metres high, will have 18 retail and commercial spaces on the ground floor and a 260 square metre space on the public observation deck which Geocon says will suit the likes of a cocktail lounge. The Republic and Dusk buildings will have 12 to 16 spaces. Stage three, which is yet to be built, will have nine.

The supermarket is just 855 square metres with the developers aiming for it to be a fully-serviced store.

Geocon wouldn't reveal the "locally known and nationally recognised brands" that will occupy the precinct once completed.

The developers say it currently had more than $70 million worth of commercial space for sale in its mixed-use projects across the ACT.

"Geocon develops mixed-use precincts at the heart of town centres carefully selected for their proximity to transport, business centres and world-class educational institutions where occupiers within the projects will thrive," Mr Nicholls said.

"With more major mixed-use precincts in the pipeline, including Wova in Woden and the arts precinct on Kingston Foreshore, Geocon's commercial business is going from strength to strength and will soon be responsible for developing around $200 million worth of commercial stores for sale or lease to businesses who wish to call Canberra home."