Orchard Central, whose layout has been criticised as complicated, will undergo its first major renovation since it opened in 2009.
Set to be completed by the third quarter of 2016, this will introduce new escalators and reconfigured walkways in the 11-storey mall, said Far East Organisation - which owns the mall.
Mr Eric Tong, Far East's assistant director of its retail business group, said this will "optimise accessibility and improve shopping experience".
He added that it will welcome a major brand that is "setting up its first South-east Asia flagship at Orchard Central".
The Straits Times (ST) understands from other tenants that Japanese clothing retailer Uniqlo will take up a three-storey space in the mall.
But the renovations come at the expense of 21 tenants, who will have to close or relocate by Dec 31.
Two of them - burger chain Everything With Fries (EWF) and eatery Central Hong Kong Cafe - have put up posters in their shops expressing unhappiness at being forced to give up their prime spaces.
EWF is near the mall's entrance on the first floor, while Central is on the second floor, next to an escalator.
Neither is taking up the offer to relocate within the mall.
Ms Jun Low, director of JC Global Concepts which owns the Central cafe, told ST that Far East had informally offered her another spot on the second floor.
But after she hired contractors for the move, the landlord later said it has found tenants better suited for that space, and tried to persuade her to move to other floors, she claimed.
"There was no formal letter of offer, but there's such a thing as business ethics. So I declined," she said.
"I feel we are very marginalised, being smaller tenants."
The lease for her 2.5-year-old eatery was due to end in August 2016, but will now be terminated without any compensation for her, as per a clause in the contract, she added.
A spokesman for EWF, a tenant for five and a half years, said it rejected the alternative spot as it was "not feasible" for its concept.
"The poster was just to thank customers and not for publicity," added the spokesman.
A ST check last week found that most of the affected tenants are in the first four floors of the mall and have closed.
At least two - shoe shop Walking Tall and craft store Beads.etc - are moving to Orchard Gateway, next to Orchard Central. Orchard Gateway is owned by OCBC Bank and Great Eastern.
Mr Tong told ST that tenants were informed in June this year. Those affected were given offers to relocate within the mall or to other Far East malls.
Most tenants are "positive", he said.
Ms Christina Lan Ge, 34, vice-president of Perle, an Italian fashion store on the second floor, told ST: "The layout now is fragmented, people get lost.
"The changes will make it better, but the management should also do something about the power supply."
Her shop was forced to close half a day early on Saturday (Dec 12) when water seepage from heavy rain caused a blackout at the mall.
This article was first published on December 14, 2015.
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