According to eye witnesses, the six-storey building collapsed after an explosion, injuring workers, shoppers and pedestrians and cracking windscreens of nearby vehicles.
The newly built six-storey Melcom shopping complex is opposite the Neoplan Assembly Plant at Achimota and the Agricultural Development Bank(ADB).
The collapsed shopping complex is on the same compound with Fidelity Bank, Achimota branch,near the Standard Chartered Bank and another shopping mall, Sarlinesta.
Meanwhile, unconfirmed reports say two persons have been rescued, dozens feared dead.
The police and National ambulance service have been able to rescue some of the victims while others are still shouting and screaming under the caved-in building.
Melcom Limited is Ghana's largest chain of retail department stores.
UPDATE : 3:56 pm
At least five people have been rescued while about 35 more are known to be trapped, said Freeman Tetteh, Greater Accra Regional Public Affairs Officer of the Ghana Police.
"I was on my way to the shop when l saw it crumpling down," Kojo Boadi, an eyewitness, said.
President John Mahama declared the scene a disaster zone and cut short his election campaign in the north of the country to be able to visit the site. The presidential election is scheduled for December.
The Six-story store opened in February is part of the Melcom chain owned by Indian immigrant magnate, Bhagwan Khubchandani. His late father arrived in Ghana in 1929 as a 14-year-old to work as a store boy in the-then Gold Coast. The store sells a variety of cheap, imported household goods and appliances that are popular with working-class Ghanaians.