The incident took place at around 5:15 pm in the South Block office of Joshi.
"The blaze was reported from an airconditioning duct. It was a minor incident. There was smoke and we suspect it to be a case of short circuit," the officials said.
It was not clear whether the Navy Chief was in his room when the incident took place.
Officials of Delhi Fire Services and Delhi Police rushed to the spot soon after the incident.