TOKYO -- The luster of Prime Minister Junichiro Koizumi appears to be dimming a bit as support for his cabinet dips in Tandem with Japan's stock market, but his ruling bloc still appears set for a victory in a weekend election. Support for his cabinet slipped to 69 percent from 85 percent a month earlier, showed an opinion poll published on Tuesday and conducted by the **Nihon Keizai Shimbun newspaper last week. A weekend survey by the daily Yomiuri Shimbun showed support slid to 72 percent from 84.5 percent in June. While other recent polls have also shown a slide in Koizumi's support levels, which at one stage were at historic highs of more than 90 percent, the charismatic, silvery maned politician is still by far the most popular leader in post-war Japan. Analysts have said growing concern about the ailing economy and questions over whether Koizumi will be able to enact promised reforms are having an impact on his ratings, Reuters reported. Some critics have said Koizumi has failed to provide details of his reform plans. Once the election is over, he will face increased pressure to move quickly to prove he can carry out pledges to drag the economy out of its a decade-long slump. In a sign he may be heeding such criticism, Koizumi told Economic Minister Heizo Takenaka that the government should accelerate its planned reforms. Stock Concerns "The prime minister has been saying that we should not react to every movement (in the stock market)," Takenaka was quoted by Jiji news agency as telling reporters after meeting Koizumi to discuss the dive in Tokyo shares to a 16-year low on Monday. "He said we should press ahead with reforms, including their early implementation." The Tokyo stock market's Benchmark Nikkei average slid to a 16-year closing low on Monday, undercut by falls in major banks of a worsening economy and policy stagnation would batter their bottom lines. It ended Tuesday morning trade up slightly. The number two executives of Japan's three coalition parties said they shared worries about the impact of the drop in Tokyo share prices on the fragile economy, Jiji said. The trio agreed to support Koizumi's planned structural reforms and consider steps to boost employment at a possible extraordinary Parliament session in the autumn, Jiji added. The reform plans got a vote of confidence from U.S. Secretary of State Colin Powell on Tuesday. "Our government fully supports Prime Minister Koizumi's economic reform agenda and we stand ready to assist in any way we can," Powell told a news conference near the end of a brief stop in Tokyo at the start of a five-day Asian tour. Koizumi's three-party coalition already holds a majority in the Upper House of Parliament but needs a good showing in Sunday's polls to gain a mandate to implement painful but necessary reforms of an economy now sliding into recession. Despite some growing disappointment over Koizumi, his coalition government appears set to fare well in the election and to win at least the 63 seats needed to maintain its Upper House majority. There are 121 seats up for grabs. Majority Seen Likely The ***Mainichi Shimbun*** newspaper said the number of seats the coalition would win would be in the mid-60s, while the Asahi Shimbun forecast the ruling bloc could take as many as 75. Koizumi's long-dominant Liberal Democratic Party (LDP) alone claims it will take 61 seats. Koizumi needs the LDP to perform well if he is to survive a party presidential poll in September. Analysts warn, though, that an overwhelming win for the LDP could strengthen the hand of koizumi's old guard opponents, making it harder for him to carry out reforms. Koizumi has said that he can forge ahead with his reform agenda as long as his support stays at around 40 percent.