Japan's largest labor organization, the Japanese Trade Union Confederation (Rengo), is poised to pare back its support for the newly formed opposition Democratic Party, sources said Wednesday.

Its decision-making central executive committee on Thursday will consider a proposal to change the wording in Rengo's statement on the party from pledging "cooperation and support" to just "cooperation," the sources said.

The Democratic Party of Japan merged with the smaller — and broadly more conservative — Ishin no To (Japan Innovation Party) last month to form the new party, the largest opposition party in Japan.

The proposal reflects a desire among Rengo members to wait and see how much sway former Ishin members have on Democratic Party policy. Rengo represents about 6.82 million members of unions throughout Japan.

Rengo could restore the more proactive stance if the policies espoused by the newly formed party are judged to be in keeping with the union body's own policies and political ideals, the sources indicated.

"(In that case, Rengo) will sign a policy accord (with the party) in the run-up to the House of Councilors election this summer," a source said.

The party is fielding 12 Rengo members among its candidates for proportional representation districts in the Upper House election.

Rengo's current policy statement says the organization will "strengthen cooperation with and support of the DPJ, which shares most of our policies, and aim to see those policies realized."

And in a policy accord for the 2014 Lower House election, the union body pledged its "full support" to the DPJ.