Myer occupies three levels at the mall, and its closure will leave the department store with just one outlet in Canberra - in the Canberra Centre in the city - after it closed its Tuggeranong store in 2012 and it abandoned plans to open at Westfield Woden in 2014.

Myer date the closing date was subject to "discussions with the landlord", but Westfield said the store would not close until Myer's lease runs out in July 2019.

Shop, Distributive and Allied Employees' Association (SDA) NSW/ACT branch secretary Bernie Smith said the store employs between 60 to 70 people on a casual, part-time and full-time basis.

He said a workplace agreement meant Myer cannot force redundancies and permanent employees must be given the option of another position.

"We were surprised and concerned for our members," he said.

"One good thing is there's a long lead time before it will actually take effect."

Belconnen Community Council committee member Damien Haas said it was a blow the store, which had been a fixture of Belconnen since 1978, was closing.

He said the community council had invited Scentre Group - the owner of Westfield shopping centres in Australia - to its community meeting next week to discuss future development options at Westfield.

"People have this attachment to places like Myer, when something has been there for decades and then it's not it can be quite a big deal," he said.

"Obviously it's going to be an enormous impact to the Belconnen community."

Regular shopper Tessa Bailey, 19, said she was disappointed Myer was closing because it was an easy and convenient place to buy all the beauty products she needed.

"I used to come here with mum when I was growing up, it was where I first discovered all the beauty brands I love," she said.

Westfield's head of corporate affairs Julia Clarke said Myer would close in mid-2019 and it was a chance for the shopping centre to "update its retail offer".

"Their departure will enable us to introduce new retailers - both local and international - into our centre in 2020 – allowing our offer to remain fresh and relevant," she said.

Canberra Business Chamber CEO Robyn Hendry said the closure could be a major blow to Westfield Belconnen if it didn't have other anchor tennants lined up.

"They wouldn't want that space vacant nor would their other tenants because these things work as a dynamic environment," she said.

"Naturally the flow on effect to employment is immediately concerning, loss of jobs of any sort is never a good thing."

Ms Hendry said there was a global trend away from large generic providers to more specialised stores.

"Other interesting factors you can't ignore is the fact ACT has the highest online per capita expenditure in retail space across Australia," she said.

The company announced three stores - Colonnades in Adelaide, Belconnen and Hornsby - would close amid sluggish sales and profits naitonally.

The department store giant today released its financial results showing a 1.9 per cent dip in profit for the 12 months to the end of July.

"Today we are announcing that we will not be renewing leases at Colonnades, Belconnen and Hornsby. Since the launch of New Myer in September 2015, we have closed or announced the closure of 74,670square metres of store space overall," Myer chief executive and managing director Richard Umbers said.

"We are obviously disappointed to have not reached our target of exceeding last year's NPAT of $69.4 million and that progress against our metrics that matter is slower than we anticipated."

Myer said sales in the first six weeks of 2017-18 were "below expectations".