Chief negotiators from the 12 countries thrashing out the Trans-Pacific Partnership worked on last-minute preparations Wednesday before their ministers and leaders gather in Bali, Indonesia, with the aim of reaching a basic agreement on the free trade pact.

"We have been able to arrange what we will report to the ministers, and substantive discussions are in progress," chief Japanese negotiator Koji Tsuruoka told journalists before the start of the second day of their latest talks.

Noting that the chief negotiators are receiving reports from working groups, Tsuruoka added, "I think we are making progress as scheduled."

The chief negotiators have been tasked with sorting out issues for political decisions by the ministers at meetings starting Thursday, followed by the summit next Tuesday.

The TPP meetings are being held on the sidelines of the Asia-Pacific Economic Cooperation forum gatherings, which started its senior officials' meeting Tuesday.

The 12 nations are hoping to reach a basic agreement this year to clear the way for concluding negotiations by the end of the year.

During the first day of the talks, the negotiators discussed five out of 21 fields covered by the envisioned pact and were expected to address some of the remaining fields that require sorting out before the ministerial meeting.

The topics are likely to include intellectual property rights protection rules and the treatment of state-owned enterprises, on which countries still need to narrow severe gaps to reach a basic agreement.

The 12 countries taking part in the Trans-Pacific Partnership talks are Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.