South Korea is ready to work with members of the QUAD - namely, Australia, India, Japan and the U.S. - on an issue-by-issue basis.
Diplomatic sources in Seoul proposed areas in which the country can cooperate including responding to the Covid-19 pandemic and climate change.
Seoul also maintained its stance that it has not received an official request from the QUAD to join the forum.
The Quad is seen by many as a U.S.-led coalition to counter China, leaving South Korea in a tough spot between Washington and Beijing.
Watchers say there's no concerted agreement within the Quad about a possible expansion.
South Korea remains cautious anyway, saying it can cooperate with any consultative body that's "open, transparent and inclusive."