Kakadu National Park in the Northern Territory is set to be expanded, with the inclusion of land previously earmarked for uranium mining.

The Northern Land Council (NLC) has agreed for a 1,200 hectare parcel of land containing rich reserves of uranium to be incorporated in to the park.

It is considered the final step in a long battle that Aboriginal traditional owner Jeffrey Lee has waged to protect his land from mining.

The uranium-rich mining lease Koongarra was excised from Kakadu when the conservation area was established in the late 1970s.

The lease is held by French company Areva, which wanted to mine the area for uranium.

Two years ago, Mr Lee, the sole traditional owner of the land, called on the Federal Government to incorporate it in to Kakadu.

The Government accepted the offer and referred the matter to the NLC.

The NLC conducted consultations and its full council has agreed to endorse Mr Lee's wishes.

The council and land trust will now move to enter an agreement with national parks to incorporate Koongarra into Kakadu.

NT Environment Centre director Stuart Blanch says he welcomes the decision.

"It is a great day," he said.

"It is the right thing to do, and it just shows you some of the great conservation Aboriginal people do here in northern Australia."

It is not known if Areva will attempt to take any action over the decisions.

The existing Ranger uranium mine is located within the boundaries of Kakadu, about 180 kilometres south-east of Darwin.