Residents who were evacuated ahead of Cyclone Trevor lashing the Northern Territory coast have begun to return home as the weather system moves inland and weakens to a tropical low.

But the threat is not over for communities near Tennant Creek, 500 kilometres inland, as the Bureau of Meteorology on Sunday warned of heavy rain and destructive winds in the NT's east.

Cyclone Trevor has slowed to a tropical low. Credit:Bureau of Meteorology

The ex-cyclone crossed onto the mainland as a category four storm on Saturday morning, producing wind gusts of 230km/h around the NT's border with Queensland.

Shortly after midnight on Sunday, the storm was downgraded to a tropical low.