New Japan PM expresses regret for slush fund scandal

"I will achieve politics that is not for politicians but for the people," Ishiba said on Friday, pledging to provide sincere explanations and ensure MPs abide by the rules.

He set five policy pillars to uphold, including security, economy and disaster resilience.

Ishiba said he would bolster Japan's military capability to defend itself from threats from China, Russia and North Korea under the framework of the Japan-US security alliance.

He did not mention two goals he advocated before taking office - making the Japan-US security alliance more equitable and establishing a NATO-like collective defence system in Asia - apparently to avoid controversy before the election the LDP must win.

Omitting those goals also saves him from possibly irking Washington, but might disappoint those who saw him as willing to speak up even when he risked disagreement with his own party.

Ishiba noted violations of Japanese airspace in September by Chinese and Russian warplanes and North Korea's advancing missile technology and testing as examples of the worsening security environment that Japan faces and stressed the need for a further build-up of Japan's military.

He said he would promote a "strategic, mutually beneficial relationship" with China and increase communication on all levels to build "stable and constructive" ties.

He also said he would further strengthen and expand Japan's ties with South Korea and the trilateral co-operation Japan has with it and the United States.

The first public support ratings for Ishiba as prime minister were about 50 per cent or even lower, the lowest levels for a new leader, according to Japanese media.

Opposition leaders have criticised him for rushing to hold an election after only adding a new face and fresh image to the party without any concrete results. 

He plans to dissolve parliament next Wednesday for an election on October 27, allowing only a few days of debate on his policies.