The commercial arm of the Dunedin City Council is reporting a solid half-year financial result.

Dunedin City Holdings revenue for the six months to December was up 9% to just over $128m.

The investment group has had higher operating cash flow, paid off more of its debt, and posted a $10m after-tax profit.

Chairman Graham Crombie is pleased with the results, saying it's ultimately a good outcome for ratepayers, who are the shareholders of the group.

Aurora Energy, Dunedin International Airport and Taieri Gorge Railway are all seeing increased profits, while City Forests and Delta are slightly down on business.