Northern Territory Chief Minister Terry Mills says he will lobby the Federal Government and Opposition to guarantee support for the construction of a gas pipeline between the Territory and Queensland.

Mr Mills told the Legislative Assembly the pipeline should be built from Tennant Creek in the Territory to Mount Isa in north-west Queensland to encourage growth and investment.

He says the project is now on the COAG agenda, which is proof of its national significance.

"This is a big, bold plan, a very important plan," he said.

"It is part of the Country Liberals' DNA as to have these sorts of plans that are going to create a better future for the Northern Territory."

The proposed pipeline would cost an estimated $500 million.