The Power and Water Corporation says tariff increases will be used to fund building and maintaining infrastructure, not rein in debt.
The Northern Territory Government has increased power prices by 30 per cent and water costs by 40 per cent in a bid to make the corporation more financially sustainable.
Those increases started to apply from January 1.
Power and Water managing director Bertram Birk says it will take time to improve the corporation's finances.
"We had a major asset failure in Casuarina a few years ago," he said.
"We embarked on a massive expenditure program to replace those old assets, and install a lot of new equipment.
"We've still got a couple of years of that work to go, and the tariff increases are necessary to fund that equipment and infrastructure upgrade." Mr Birk says most people will see a transition to increased power prices when they next receive their bills.
"Most people will receive an account every three months, so if there's two months of the account on the old tariff and one month on the new tariff, that's just a bit of math applied to the bill," he said.