"A problem" with the generators at the gas-fired Channel Island power station copped the initial blame which saw power cut to Katherine, Palmerston, Darwin and other Top End communities during the sweltering build-up heat from 4pm.

The outage lasted three hours for many.

Katherine Hospital was forced onto its back-up generators during the blackout which saw traffic lights out and businesses forced to close.

The blackout was triggered just after 4pm, and a slow restoration process began after the fault had been repaired just after 6pm.

Power officials said a gas problem at Channel Island, the NT's biggest power station, had been fixed.

The first units at Channel Island, in Darwin Harbour, were commissioned in 1986, and Channel Island now has 310MW of installed capacity. It is a gas-fired station, with diesel fuel back-up capability.

While you're with us, you can now receive updates straight to your inbox each Friday at 6am from the Katherine Times. To make sure you're up to date with all the news, sign up here.