Australian Trade Minister Andrew Robb said substantive issues remained in trade negotiations with Japan as the two nations rushed to conclude a free trade agreement before their prime ministers meet on Monday.

"We made progress. There are still a couple of substantial issues we are negotiating and we will meet again tomorrow," Robb said after a five-hour session with Agriculture, Forestry and Fisheries Minister Yoshimasu Hayashi in Tokyo on Saturday. Robb described the meeting as exhausting.

Hayashi said later there had been a "frank exchange of opinion." He said he would report on the progress to Prime Minister Shinzo Abe, who will meet Australian Prime Minister Tony Abbott in Tokyo on Monday.