TOKYO — In a contentious move that could make or break his government, Prime Minister Yoshihiko Noda said Friday that Japan would join talks toward an ambitious pan-Pacific free trade pact. The accord would potentially open up new markets for Japanese exporters but enrage the nation’s powerful farmers, who say their livelihoods would be wiped out.

Mr. Noda is set to declare Japan’s intent at the Asia-Pacific economic summit meeting in Hawaii this weekend, where President Obama will promote the far-reaching Trans-Pacific Partnership regional trade agreement, which aims to cut import tariffs to zero. Nine governments, including those of Australia and Singapore, are involved in the discussions.

Speaking at a nationally televised press conference, Mr. Noda contended that global competition would ultimately build a stronger domestic economy, including a more competitive agricultural sector. He invoked his own farming roots, reminiscing about being carried on his mother’s back as she helped till the fields at her family’s farm.

“The smell of dirt forms the very basis of my childhood memories,” Mr. Noda said. “I am determined to preserve Japan’s traditional culture, its beautiful farming villages. But in order for Japan, which has built its prosperity on trade, to pass on its affluence to future generations, it must tap into the vitality of the Asia-Pacific region.”