Officials from the United States and 11 other Pacific Rim countries failed to seal a final agreement on the Trans-Pacific Partnership (TPP) trade deal "in principle" on Sunday as scheduled, shedding light on the divisions among the 12 parties.

Trade officials originally scheduled to wrap up talks on the agreement on Thursday, but have not yet worked out major differences in the areas of agricultural market access, rules of origin for autos and intellectual property protections for a new class of drugs known as biologics.

The TPP talks, gathering countries that make up about 40 percent of global economy and believed to be the biggest trade agreement in the world in the past two decades, are said to have entered the final stage after more than five years of negotiations.

Zealously pushing forward the TPP, Japan's Economy Minister Akira Amari had said he was expecting a deal "in principle" to be announced Sunday afternoon, but a press conference on the announcement was delayed and eventually canceled by US trade officials with no reasons given to the public.

Australian Trade Minister Andrew Robb said the delay on Sunday came as other TPP partners reviewed the proposed terms of a compromise on the monopoly period available for biotech drug companies.

Although Mexico has decided to compromise on biologics, New Zealand was said to be pressing on Sunday for greater access to overseas markets for its dairy exports.

Meanwhile, trade unions, environmental groups, consumer and heath care organizations in several countries have been protesting against the TPP due to various concerns.

Whether the TPP could taken into consideration the benefits for developing countries with disadvantages in competitiveness in certain fields is also a highly controversial issue.

While every country at the table has seen its fair share of doubters about the value of the TPP, three Latin American countries, namely Mexico, Chile and Peru have been heard somewhat less than others.

Topics such as extended patent protection periods for biotech drugs and trade barriers and local content regulations for cars and auto parts were major hurdles for them.

For its part, China's Ministry of Commerce earlier expressed hope that the TPP can be transparent and open, and contribute to free trade and investment along with other arrangements in the region.

While TPP countries could get another chance to continue negotiations on the sidelines of the Asia Pacific Economic Cooperation summit in the Philippines in November, failure to strike a deal in Atlanta could also deliver a major blow to Barack Obama administration's trade agenda and raise questions about its capability and credibility.

The TPP talks involve Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.