South Korean officials have said President Moon Jae-in could attend a possible summit between Donald Trump and Kim Jong-un.
Any attendance by Mr Moon would be dependent on the progress of pre-summit talks between the US and North Korean leaders, said the Blue House.
The historic meeting is scheduled to take place on 12 June in Singapore.
It has been thrown into uncertainty, after Mr Trump said he would no longer be attending.
But both sides have since been working to get it back on track.
It would be the first ever meeting between a North Korean leader and a sitting US president.