The home side led 17-5 at the break.
Central Southland took a while to warm up, but pounced with two second-half tries to set up a close finish.
Dunstan coach Dennis Mullally said his team had to dig deep to get the victory.
‘‘To be fair, Central Southland played well in the second half,’’ he said.
‘‘They come back and it could have gone either way.’’
No8 Mason Maguire made some powerful runs for Central Southland, and Declan Schouten impressed in the midfield.
But Dunstan tighthead prop Wade McAtamney and captain Otis Battrick tackled everything that moved and were not surrendering the lead at all costs.
Centre Hayvin O’Neill kicked both conversions and two penalties, which was a big help.
Fullback Reuben Mills was dangerous in the opening half.
In the other division 2 games, Southland Boys’ 2nds beat Wakatipu 24-12 in Queenstown, and Waitaki Boys’ had a comfortable 29-10 win over Otago Boys’ 2nds in Oamaru.
In division 1, King’s destroyed St Kevin’s 90-7 in Oamaru, and John McGlashan beat South Otago 38-19 in Dunedin.
Taieri continued their bright season. They beat King’s 2nds 38-22 in Mosgiel in a division 3 game.
In the other division 3 games, Hokonui beat Mount Aspiring 34-7 in Edendale, and Timaru Boys’ 2nds beat Cromwell 39-10 in Cromwell.
