The U.S.-led agreement is a major part of President Barack Obama's foreign policy shift toward Asia but has been snagged by disagreements between countries on market access, especially for agricultural products, environmental protections and intellectual property.
Washington had said it hoped the trade agreement would be completed by the end of the year.
After four days of meetings in Singapore, ministers issued a statement Tuesday saying that "substantial progress" had been made on finalizing the Trans-Pacific Partnership. It said they had identified "potential landing zones" for most of the outstanding issues and would meet again next month.
Deborah Elms, a professor at Singapore's Nanyang Technological University, said the tone of the statement suggested negotiators have a "pretty clear understanding" of what a final agreement would look like.
Elms, who follows the negotiations, said she expected a deal to be finalized in March. Others have predicted similar.
"It's easy to get a quick agreement: you just drop the level of ambition. There was no temptation to do that," U.S. Trade Representative Michael Froman told reporters in a conference call after the talks. He said the 12 countries are focused on reaching a "high-standard" agreement.
Negotiators are aiming to reduce tariffs on goods and services to close to zero. They are also trying to ensure that foreign companies operating in those markets have a level playing field with state-owned ones, and that their products are not counterfeited.
The block includes developing countries with large state-owned industries such as Vietnam and Malaysia as well as rich nations including the United States and Japan.
The agreement would encompass around one-third of world trade and 800 million people. Proponents say it should lead to greater economic growth.
Any deal will have to be ratified by the U.S. Congress, where Democratic lawmakers in particular are calling for tough provisions on environmental and labor standards and against currency manipulation. To simplify ratification, the Obama administration wants Congress first to pass legislation that gives it authority to negotiate trade deals that Congress can accept or reject but cannot change.
Non-governmental organizations have also been seeking to influence the agreement to get a better deal for the poor.
They fear that the cost of medicines may rise in countries such as Vietnam because U.S. pharmaceutical companies are pressing for long periods of patent protection, slowing the release of generic versions of drugs.
The talks in Singapore followed a World Trade Organization summit in Bali last week at which the organization's 159 member economies agreed to cut customs red tape. It was the first WTO deal since the global trade body was formed in 1995.
The countries negotiating the TPP are Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.