Prime Minister Junichiro Koizumi's policy speech to the Diet on Friday was full of wishful goals but lacking specifics, the head of the largest opposition party said.
"The speech was equal to that of a first-time candidate (for the Diet)," said Naoto Kan. "I was really disappointed."
Koizumi has been prime minister for 2 1/2 years.
Kan heads the Democratic Party of Japan, which on Wednesday absorbed the Liberal Party to create an opposition force with 204 Diet members.
He said that during the Diet session, the DPJ will propose specific policies that it would pursue if the party manages to unseat the Liberal Democratic Party-led coalition in the coming Lower House election.
"We want to combine our forces to win more than 100 seats in the election and take over power," DPJ Secretary General Katsuya Okada said earlier in the day.
LDP Secretary General Shinzo Abe meanwhile said his party wants to hold "constructive discussions" with the opposition camp during the Diet session, calling for their cooperation for smooth passage of a government-sponsored bill to extend a contentious antiterrorism law by two years.
The bill would extend the mandate for the Self-Defense Forces' logistic support for the U.S.-led military operations in Afghanistan. The original law expires Nov. 1.
"There's no time to lose for this law," Abe said. "We've played an important role, and I want (the other parties) to consider whether the international society would continue to trust us if we abandon this role halfway."
The DPJ has not yet forged a consensus on whether to support the bill, while the Social Democratic Party, a minor opposition force advocating a pacifist security policy, said it is "firmly resolved to oppose" the bill.
"The mission for the special antiterrorism law has already ended," the party said in a written statement.
