The Northern Territory Chief Minister has confirmed Japanese company Inpex has delayed its investment decision in a $12 billion LNG project in Darwin.

Paul Henderson is in Japan and has been meeting with senior members of the gas company.

Inpex was originally due to make its decision by late this year, but this could be pushed back as far as 2011.

Mr Henderson says the company has delayed its deadline because preparing costings and designs for the project is very complex.

"Eight million tonnes per annum of LNG to Japan, which is what this plant will be producing, is about 10 per cent of Japan's LNG requirements," he said.

"So it's an enormous project, it's a very complex project, the engineering is very complex and a final investment decision is going to be made end of 2010, beginning of 2011."

Meanwhile, the Territory Government says Inpex has signed a memorandum of understanding for Indigenous people to get jobs if the company builds the gas plant in Darwin.

The Government says Inpex signed the MOU with the Larrakia Development Corporation late yesterday.