TOKYO (AFP) - Tokyo governor Yuriko Koike is a media-savvy political veteran who has charmed her way through Japan's male-dominated political world and now played a wild card that threatens to reshape national politics.

The charismatic former television anchorwoman has launched a new party that aspires to offer an alternative to the long-governing Liberal Democratic Party and its leader Prime Minister Shinzo Abe in upcoming snap elections.

Displaying a knack for political theatre, she announced she would lead the new "Party of Hope" in a surprise news conference just hours before Abe himself declared snap polls - pulling the rug from under the premier's feet.

And the telegenic 65-year-old also knows how to hog the media limelight - just minutes before her news conference, she was being pictured alongside images of a baby panda, recently named in a Tokyo zoo.

Koike, who was elected Tokyo governor only a year ago, combines a natural understanding of the media with a knack for sniffing out good political fights and opportunities for advancement, analysts say.

A trailblazer who became the first woman in many jobs, such as defence minister and governor of the capital, Koike has played on her natural appeal and reformist zeal to win over both voters and some in the old-school political world.

The party's first campaign video shows a woman presumed to be Koike - viewers don't see her face - in high heels and a snappy business suit barging her way past a bunch of stuffy old men.

Koike has complained that Japan has not just a glass ceiling but an "iron plate" holding back women.

"She is a person who clearly enjoys politics. She has a natural intuition," said Tomoaki Iwai, professor of Japanese politics at Nihon University.

"She is quick to make decisions. She doesn't dwell on things. She knows the media extremely well," said Iwai, has known Koike for a long time.

"Because she is intuitive and not a plotter, she comes off as a good sport," he said.

Fluent in English and Arabic, Koike projects an image as an internationalist rarely seen in navel-gazing Japanese politics.

Born in 1952 in Ashiya city in western Japan, Koike attended the region's Kwansai Gakuin University before graduating from the Cairo University of Egypt in 1976.

After a stint as a translator, she worked as a television broadcaster, interviewing Libyan leader Muammar Gaddafi and Palestinian Liberation Organisation chair Yasser Arafat.

Harnessing her now nationwide fame, she first won an upper house seat in 1992 before switching to the more-powerful lower house in the following year.

Koike has frequently changed political affiliations but always stayed close to powerful bosses, such as former prime ministers Morihiro Hosokawa and Junichiro Koizumi as well as Ichiro Ozawa, a shrewd strategist who for decades had wielded significant political influence.

She joined the LDP in 2002, and became environment minister in 2003 in the popular Koizumi administration.

From 2005, she began promoting "cool biz", pressing Japanese businessmen to take off ties and jackets during summer in a drive to conserve energy for air-conditioning.

In September that year, she joined a star-studded cast of female candidates sent out on the campaign trail by then prime minister Koizumi. The women - referred to in the national media as Koizumi's assassins or lipstick ninjas - also include Satsuki Katayama, a model-turned-bureaucrat, and Makiko Fujino, Japanese television's version of Martha Stewart.

Their mission: to take out the prime minister's political enemies in the old boys' network that long held sway over the LDP.

At a news conference to officially launch a new party on Wednesday (sept 27), she vows to shake up the upcoming snap election in Japan and old-school politics in Japan.

Pledging to bring back "hope" to the Japanese people, Koike said the party aimed to "reset" the country, which is expected to go to the polls on October 22.

"Now is the time for us to carry out reforms that are un-tied to" vested interests, she told a nationally televised news conference.

She used to work with Abe during his first short stint as a prime minister a decade ago when she was tapped as his special adviser on national defence before being appointed the first woman defence minister in 2007.

But she had only lukewarm support inside the LDP and failed in a bid to become party chief.

Last year she made a spectacular comeback when she ran as an independent and won a landslide victory against the LDP's candidate in the Tokyo gubernatorial election.

She went on to batter the LDP again in the Tokyo assembly election in July, but she has carefully maintained cordial ties with Abe, and vice versa, as they have to work together on putting on a successful Tokyo Olympics in 2020.

Koike has already rallied several disillusioned lawmakers from other weak opposition parties to her cause but commentators say she may lack sufficient time to mount a serious national challenge to Abe.

With the 2020 Olympics fast approaching, Koike has vowed to stay on as governor of Tokyo, meaning she won't run herself for a seat in the parliament.

However, if her group were to win 20 to 30 seats in parliament, it could tip the balance of power, said political analyst Iwai.

Critics say she lacks a clear message that differentiates her group from the tattered Democratic Party, the main opposition party.

"Mr Abe is not going away anytime soon. So she originally envisioned a small group, maybe five to 10 people, whom she could control remotely," Iwai said.

"Now, it's serving as a shelter" for lawmakers fleeing their parties, Iwai said.

"Her policies may be haphazard. But a sense of unity would come once she gets people elected," he added.