Daily News Sri Lanka, in its account of the minister's visit, said 15 storage tanks were being built on 20 hectare site close to the new port, which has been named Magampura Mahinda Rajapaksa.
It said the tanks would be used to store bunker fuel, aviation fuel and liquid petroleum gas (LPG).
Earlier reports have spoken of an 83,000 metric tonne (mt) capacity tank farm, where some 55,000 mt capacity would be set aside for marine fuel.
Last month, Lanka IOC, together with Lanka Marine, conducted the first bunkering operation at Hambantota.
But there is still confusion about which bunker companies will be given approval to operate in Hambantota in the longer-term.
Lanka IOC, a subsidiary of Indian Oil Corporation Ltd, has said it would like to expand operations at the port, which it says is in "a very strategic" location for ship refuelling.
The Sri Lanka Ports Authority (SLPA), however, has yet to finalise plans for bunker at Hambantota, although it has said the sector would be closed to outside investors.