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.
But 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 meeting between sitting leaders of the US and North Korea.
Last week, Mr Trump said he was pulling out, blaming the North’s “open hostility”. He later said the US was talking to North Korea and it could still go ahead.
On Sunday, Mr Trump said a team from the US had arrived in North Korea to make arrangements for the summit, saying it would help the North achieve its “brilliant potential”.
Separately, Mr Kim and Mr Moon held a previously unannounced meeting on Saturday, following their groundbreaking meeting in April.
The Blue House said on Monday that discussions on Mr Moon’s potential involvement in the US-North Korea event were at an early stage.
“We are still waiting to see how they come out, but depending on their outcome, the president could join [Trump and Kim] in Singapore,” the official told news outlet Yonhap.
Trump-Kim summit: President Moon could attend, says South Korea}