The blaze started around 6:30 pm on Monday in an open plot near an IT Park along the General Arun Kumar Vaidya Marg in the western suburb, located adjacent to the Colony.
Nearly 3,500 staffers were working in the building in the Mazagon area in South Mumbai when the fire broke out around 12.30 pm, Maharashtra Deputy Chief Minister Ajit Pawar said. He assured a probe into the the fire, but clarified that no records were lost in the blaze due to digitisation of documents.
Fire brigade officials admitted that organisers of the event had not complied with nearly 10 fire safety measures.
Two fire brigade officers were seriously injured while as many went missing and were feared trapped under the debris.
Five people, including a woman, were killed and three others were injured after a three-storey building in Kamathipura area in south Mumbai collapsed on Saturday.
The massive blaze in a high rise in Mumbai that killed seven people and injured 18 others was caused apparently by a blast in an air-conditioner.
This is the second major building collapse in the city in just over a month.