The Greens say a uranium scare in Kakadu National Park is evidence mining there should not be allowed to expand.

Part of the Arnhem Highway in Kakadu National Park was blocked for three hours yesterday while two containers of uranium oxide were lifted off a bogged truck.

The radioactive material was being transported from the Ranger mine.

Miner Energy Resources Australia says nothing was spilled.

The Greens say it is another reason why plans to expand the mine should be rejected.

Senator Scott Ludlam says Energy Resources Australia has a poor track record.

"This isn't an isolated incident. Right from the beginning this mine has been plagued with difficulties with accidents, spills and near misses," he said.

Energy Resources Australia says it will submit an environmental impact statement for the planned mine expansion later this year.