A third option being considered is the city centre, though this will be more challenging to do because of the cost and land required, he said.
"I shared some of the considerations and possibilities with the Prime Minister, and this is something that we are working on and we will decide within the next year or so," said PM Lee.
He was speaking at a joint press conference with his Malaysian counterpart Najib Razak, wrapping up a two-day Malaysia-Singapore leaders' retreat here.