Japanese prime minister Shinzo Abe has told Myanmar’s leader that a credible investigation into alleged human rights violations against Rohingya Muslims is key to resolving the crisis.

Abe told a joint news conference after talks with Aung San Suu Kyi that Japan would support efforts by Myanmar to accommodate Rohingya who returned home from refugee camps in neighbouring Bangladesh.

“This problem is complicated and serious, and Japan will think with Myanmar and support its effort in resolving the problem,” Abe said on Tuesday. “A credible investigation by the independent panel is particularly important.”

Aung San Suu Kyi said she welcomed Japan’s support “for our efforts for the refugees’ return.”

However, Abe’s comments came just 24 hours after the UN special rapporteur to Myanmar Yanghee Lee released a fact-finding report which concluded that Myanmar is “unable and unwilling” to investigate its abuses against Rohingya Muslims.

Buddhist-majority Myanmar’s military is accused of widespread rights violations, including rape, murder, torture and burning villages, which sent over 700,000 Rohingya fleeing to Bangladesh since August last year. A UN fact-finding mission released in August accused the Myanmar military of carrying out genocide against the muslim minority.

Myanmar authorities, including the army, have rejected independent international investigations and conducted their own inquiries which have declared their forces free of criminal actions. Under pressure from the international community, in July the government commissioned another panel to investigate Rahkine.

But Yee, who is banned from entering Myanmar because of her criticism of the regime, said the Myanmar government had proven itself incapable of carrying out an unbiased investigation, highlighting what she described as the country’s “limited and insufficient steps” so far. “The onus is on the international community to take action,” Yee warned.

Speaking during her visit to Tokyo for a six-nation Mekong regional summit, Aung San Suu Kyi promised an “accurate and appropriate” investigation. She defended the government-commissioned panel as free and effective, and its members – one each from Japan and the Philippines and two from Myanmar – as experts on human rights and international issues.

However, many have raised doubts about the panel’s impartiality and willingness to condemn any atrocities. The panel member from the Philippines, former undersecretary of foreign affairs Rosario Manalo, recently said of their investigation: “I will assure you that there will be no blaming of anybody, no finger-pointing of anybody”, while the Burmese lawyer on the panel, Aung Tun Thet, has publicly stated his disbelief that ethnic cleansing happened in Rahkine.

In a speech on Monday to Japanese businessmen Aung San Suu Kyi had also pledged “transparency” over her government’s handling of the Rohingya crisis.

She added: “I’m ready to acknowledge that we have challenges to face particularly with regard to Rakhine and with the struggles we have on the peace front.”

Myanmar commissioned the panel after rights groups called for the international criminal court to investigate the alleged abuses. Myanmar’s government, which is not a member of the court in the Hague, rejected any participation in its proceedings.