Exactly a year after it was devastated in a major fire, officials Friday said the refurbished Maharashtra's administrative headquarters, Mantralaya, here will be fully operational within six months.

The "new" Mantralaya will have all modern amenities with an ambience set to rival any international government office.

The chief minister's office and secretariat will move to the topmost seventh floor from the erstwhile sixth floor.

The main entrance of the 58-year-old building (built in 1955) would have a new security dome with the latest state-of-the-art features.

The entire building will be centrally air-conditioned and will be controlled by a building management system.

The refurbishing, which will have an open office concept, is currently underway in full swing and a part of the devastated portion of the iconic building at Nariman Point will be commissioned mid-September.

The project cost has shot up from the estimated Rs.138 crore to around Rs.200 crore, an official said here Friday.

The June 21, 2012, fire had claimed five lives and had caused extensive damage to the top three floors of the building.

After the fire, several departments and ministries on the affected floors were shifted to alternate premises at different places in south Mumbai, and officials records destroyed in the blaze were painstakingly recreated.

Later, the renovation project was given to M/s. Unity Infrastructure which started the works in November 2012. It is expected to be completed in November.