By Elaine Lies

TOKYO (Reuters) - Myanmar leader Aung San Suu Kyi said on Friday investigations were underway into the situation in Rakhine State, where many members of a Muslim minority live and where human rights workers say conflict has led to abuse of civilians by the military.

Suu Kyi, speaking on a visit to Tokyo, told a news conference the government was trying to get to the root of the matter, and would not accuse anyone until all the evidence was in, at which point any action would be taken in accordance with due legal process.

"We have been very careful not to blame anybody in particular unless we have complete evidence as to who has been responsible for what," she said, noting that Muslims had been killed as well as police officers and the government had not "tried to hide any of this".

Nobel Peace Prize winner Suu Kyi is in Japan on a five-day visit to court investment and aid, as an upsurge in violence against the persecuted Muslim minority Rohingya at home poses the worst crisis of her six months in power.

She has faced mounting criticism abroad for her government's handling of the crisis in Rakhine State, where soldiers are accused of raping and killing civilians and where aid workers were refused access until the government on Thursday agreed to allow such work to resume.

The latest bout of violence began with attacks on Oct. 9 on three police posts by insurgents allegedly inspired by Islamist militants in which nine policemen were killed.

It is the most serious unrest to hit the state on Myanmar's western border with Bangladesh since hundreds of people were killed in communal clashes in 2012.

"We are trying to get to the root of the matter," Suu Kyi told the news conference, adding everybody had to be considered innocent until proven guilty.

"We will be going through the due process and all the incidents that have taken place ... will be examined and it will be done in accordance with our laws and regulations," she said.

"We will find out what really happened and then action will be taken accordingly."

Tension between Myanmar's ethnic minorities and the majority Burman-dominated central government has prompted many groups to take up arms to fight for greater autonomy since shortly after the country's independence in 1948.

Earlier, Suu Kyi told Japanese business executives that Myanmar needed peace to carry out sustainable development.

The Rakhine military operation has sharpened the tension between Suu Kyi's six-month-old civilian administration and the army, which ruled the country for decades and retains key powers, including control of ministries responsible for security.

Myanmar's army-drafted constitution puts the military firmly in control of security matters but nevertheless diplomats and aid workers say privately they are dismayed at Suu Kyi's lack of deeper involvement in the handling of the crisis.

(Reporting by Elaine Lies; additional writing by Linda Sieg; Editing by Nick Macfie, Robert Birsel)