A group of environmentalists have called on the Territory Government to review plans for future industrial development in Darwin Harbour.

A group of 20 protesters gathered outside Parliament House today to voice their concerns about development in the harbour, including a proposed $12 billion LNG gas plant.

Save Darwin Harbour's Nick Kirlew says the Government should look at the mistakes made in Sydney's Botany Bay.

"They are really struggling to get their water clean. Many, many years ago, bad decisions were made where people and industrialisation was placed in the same location.

"The fantastic thing about Darwin is we have the opportunity to do best practise and nowhere is best practise if you have industrialisation within five kilometres of mass population."