Assistant Commissioner of Customs R S Meena said the gold was wrapped in packets and was being illegally sent through a courier company to Mumbai.
The customs authorities, while checking the cargo of the courier company, got suspicious of the packets and on opening it found 3.5 kg of gold, Meena said.
The Assistant Commissioner Customs said that in the last one month, customs authorities in the airport have seized on six occasions gold brought illegally into the country.
The cleaning staff, while working in an aircraft which had come from Bangkok, found two unclaimed bags in the toilet and police, after opening the two bags, found 24 pieces of gold each weighing about 1 kg in the bags.