The deceased, John Richard Brimley, allegedly ended life late last night, police said.
"Brimley had been depressed due to some personal reasons. He used to regularly consume sleeping pills. No suicide note was found," said an officer at Bandra police station.
Brimley had arrived in the city on May 9 for a project with about 20 to 25 other professionals, police said.
He was found on the basement floor around 11 pm yesterday by a watchman who informed the managerial staff, police said adding that Brimley was rushed to nearby Bhabha hospital, where he was declared dead.
His body was then taken to Cooper hospital for post mortem, police said adding that the New Zealand embassy was informed.
There were no external injuries on his body, police said adding that further probe was on.