The building, on the corner of Water and Exmouth Sts, was also targeted on January 2, when two fires were lit and extinguished before serious damage to the building could occur.
Fire crews from Kaitangata and Balclutha attended the blaze, which started at 2.17am, taking about three and a-half hours to bring it under control.
The building was originally a shop that had been converted to a house, but had been unoccupied for the past six months.
Power to the property had been disconnected.
Investigations were continuing, he said, and the incident had been put in to the hands of the police.
Detective Constable Robin Hutton, of Balclutha, said it did not appear accelerants were used to start the blaze.
Kaitangata Chief Fire Officer Kevin Sutton was angry yesterday that an arsonist had put his firefighters at risk in an "unnecessary" fire.
"The fire was that intense we had to fight it from the outside for starters. Once it died down in intensity, we moved inside."
Detective Constable Craig Dinnissen, of Balclutha, said police believed the fires were lit by a group of people who knew each other, and that other people in Kaitangata either knew who did it, or had suspicions.
"It is disheartening that we are not getting any information," he said.
Det Const Dinnissen said people could call the Balclutha police station on 418-0203, or the anonymous Crimestoppers line on 0508 555-111.
