More than three out of five companies in South Korea have expressed support for the country's participation in a U.S.-led regional free trade deal, known as the Trans-Pacific Partnership, citing a possible hike in exports, a survey showed Thursday.

The TPP is a multilateral free trade pact over which negotiation currently involves 12 countries including the U.S., Japan, Australia and Canada, which accounted for about 40 percent of the global economy.

South Korea expressed interest in participating in TPP in late 2013 but has not yet made an official decision on participation.

According to the survey on 762 companies by the Korea International Trade Association, 62.2 percent said that they support South Korea's joining in the TPP with 19.2 percent of them voicing "strong" support.

Small and medium-sized companies are most supportive of TPP participation than large conglomerates. About 63 percent of the SMEs surveyed said that they support it compared with 58 percent for large businesses.

The agricultural, forestry and fisheries sector is more supportive than other areas, with 69.1 percent of companies favoring the country's joining in the deal.

The electric and electronic sector came next with 67.7 percent saying so. The support ratio for cars and auto parts makers was the lowest at 52.3 percent, the survey showed.

Those polled cited a possible hike in exports to TPP member countries as the No. 1 positive impact from the trade deal. Some, meanwhile, voiced concerns that the opening of local markets to Japan could hurt businesses overall.

The survey comes as the U.S. Senate passed a bill overnight that would give President Barack Obama "fast-track" trade negotiating authority, clearing a last-remaining hurdle to concluding the TPP negotiations.

Washington aims to conclude the signing of the deal in the middle of next month at the latest. (Yonhap)