Up to 200,000 women are estimated to have been sexually enslaved by Japan during the war, many of them Korean.
It has long strained ties, with South Korea demanding stronger apologies from Japan and compensation for victims.
Earlier this year both sides agreed to speed up talks to resolve the row.
Japan's Fumio Kishida arrived in Seoul on Monday to meet his counterpart Yun Byung-Se, in what correspondents say is a significant move after hints that possible compromise solutions were being considered.