Najib, who is also finance minister, said the infrastructure cost related to the proposed LCCT in Labu would amount to RM800 million.
"I received confirmation from Sime Darby. If they are not contributing (towards the infrastructure cost), then there is no basis for the project to be considered."
Najib said the new LCCT would be built at the Kuala Lumpur International Airport (KLIA) in Sepang.
It was reported last week that the proposal for the Labu LCCT was still under discussion.
A Bernama report quoted Transport Minister Datuk Seri Ong Tee Keat as saying in a written reply in Parliament that a final decision had not been made on whether to proceed with or scrap the proposal to build the terminal.
The report said a comprehensive study was being done to ensure that the project was feasible and would benefit the people.
Ong also reportedly said AirAsia Bhd would have to bear the cost of building the new LCCT as well as take on the connectivity costs, such as constructing roads and rail tracks and other infrastructure.