Members of the ruling Democratic Party of Japan's tax panel on Wednesday authorized panel executives to negotiate with the government the timing of a consumption tax hike, paving the way for Prime Minister Naoto Kan's tax reform plan to be approved as early as Thursday.

The proposal drafted by the DPJ panel, headed by Deputy Chief Cabinet Secretary Yoshito Sengoku, stipulates raising the sales tax to about 10 percent "by around the mid-2010s," providing the economy improves, a more vague target than the government's plan to hike the tax to 10 percent in stages "by 2015."

The panel executives and the government were still negotiating the final wording.