A new regional trade pact with China is on track, the ASEAN secretary general and Jakarta's foreign minister said Thursday despite concerns from some Indonesian businesses.

The agreement between China and Southeast Asia took full effect on January 1, liberalising billions of dollars in trade and investments in a market of 1.7 billion consumers.

Association of Southeast Asian Nations (ASEAN) chief Surin Pitsuwan said Indonesia's trade ministry had sent ASEAN a letter expressing some "difficulties".

But he said there had been "no appeal for any change or any renegotiation" of the pact to establish the world's largest free trade area by population.

Indonesia's Foreign Minister Marty Natalegawa told reporters the country is committed "to respect and abide by any international agreements that we have reached, including the ASEAN-China FTA."

On the sidelines of an ASEAN meeting, he said Indonesia's trade ministry had passed to the bloc's secretariat some business sectors' concerns to see how they could be addressed within the existing free trade agreement.

"We want to know how much difficulty our member states are in but, so far, I think it's manageable and the most important thing is to keep the momentum on course," Surin told AFP at the ASEAN foreign ministers' meeting.

Indonesia has sent mixed messages over its position on the pact amid mounting opposition from local industry groups who say hundreds of thousands of jobs could be lost in a flood of cheap Chinese imports.

Indonesian trade ministry official Gusmardi Bustami said a letter requesting negotiations to delay full liberalisation on 228 tariff lines for another two years had been sent to ASEAN in Jakarta on December 31.

But Trade Minister Mari Pangestu has refused to confirm that a formal request for further protection had been sent, saying only that she had "informally discussed" the sensitive tariff items with ASEAN.

Surin said the trade ministry letter gave "some details of the situation that they are facing with the private sector" but made no direct appeal for action.

He said he did not expect the matter to be discussed during Thursday's ASEAN meeting. Trade ministers "may be exchanging views but not in order to renegotiate or open up the issues again", Surin said.

Under the pact, China and the six founding ASEAN countries -- Brunei, Indonesia, Malaysia, Philippines, Singapore and Thailand -- are to eliminate barriers to investment and tariffs on 90 percent of products.

Members that joined ASEAN later, including Vietnam and Cambodia, have until 2015 to follow.