By Shwe Yee Saw Myint and Antoni Slodkowski

NAYPYITAW (Reuters) - United Nations Secretary General Ban Ki-moon called on Myanmar to improve living conditions for its Rohingya Muslim minority on Tuesday, ahead of peace talks between leader Aung San Suu Kyi and many of the country's ethnic armed rebel groups.

Myanmar's 1.1 million Rohingya will not be represented at the conference starting on Wednesday, but the fact Ban raised their plight - and used the term for the group that is divisive in Myanmar - may add to international pressure on Suu Kyi to address the issue.

"The government has assured me about its commitment to address the roots of the problem," Ban told a news conference in the capital Naypyitaw.

"Like all people everywhere, they need and deserve a future, hope and dignity. This is not just a question of the Rohingya community's right to self-identity."

Ban and Suu Kyi met reporters as the Nobel Peace Prize laureate launched a push to end decades of fighting between Myanmar's military and ethnic rebels.

Suu Kyi has made the peace process a priority for her administration, which faces sky-high expectations at home and abroad after sweeping to power in an election last November to end more than half a century of military-backed rule.

Tensions between Buddhists and Muslims in western Myanmar, however, are not being tackled as part of that process.

Many in the Buddhist majority country regard the largely stateless Rohingya as illegal immigrants from Bangladesh, and they are not among the 135 ethnic groups recognized by law. Suu Kyi has asked foreign diplomats and leaders not to use the term "Rohingya" because in her view it is inflammatory.

Some 120,000 Rohingya remain displaced in squalid "internally displaced persons" (IDP) camps since fighting erupted in Rakhine state between Buddhists and Muslims in 2012. Thousands have fled persecution and poverty.

"I conveyed the concern of the international community about tens of thousands of people who have been living in very poor conditions in IDP camps for over four years," said Ban.

He added that if they had lived in the country for generations, all people in Myanmar should enjoy the same legal status and citizenship as everyone else. Many Rohingya families have lived in Myanmar for that long.

Last week Suu Kyi picked former U.N. chief Kofi Annan to lead a commission to stop human rights abuses in Rakhine.

PEACE CONFERENCE

Few concrete proposals are to emerge from this week's talks, with delegates expecting to meet every six months to discuss issues ranging from security, political representation and culture to sharing the fruits of Myanmar's mineral riches.

The gathering has been compared to the Panglong Conference, a meeting between Suu Kyi's father, Myanmar's national hero General Aung San, and ethnic minorities in 1947 that led to the formation of the Union of Burma after independence from Britain.

"The 21st Century Panglong conference is a promising first step," said Ban. "I congratulate all participants for their patience, determination and spirit of compromise."

The fact that Suu Kyi has been able to bring the vast majority of the rebels to the negotiating table only five months after taking power is a sign of progress, experts say.

Powerful armed groups from regions bordering China, who refused to sign a ceasefire last October under the previous military-backed government, are now set to take part, partly owing to China's tacit support for the talks.

As Myanmar's economy opens up, China is vying for influence with the United States. President Xi Jinping pledged his country would play a "constructive role" in the peace process when Suu Kyi visited China this month.

Suu Kyi is traveling to Washington in September where she is likely to face questions on the treatment of the Rohingya.

Myanmar has been torn by fighting between the military, which seized power in the 1962 coup, and ethnic armed groups almost without a break since the end of the Second World War.

Casting a shadow over the talks is a recent flare-up in fighting in northernmost Kachin State and clashes in northeastern Shan State, which is home to several large groups operating close to borders with China and Thailand.

The still-powerful military has also strongly opposed talks with three groups that fought it in the remote Kokang area last year unless they disarm. The groups have said they cannot, citing continued pressure from the army. It was unclear whether they would be allowed to attend the summit.

Ethnic delegates have complained about what they saw as an arbitrary schedule set by the government.

Suu Kyi, who said little at Tuesday's joint appearance with Ban, has not consulted the groups about the date of the conference or the specific agenda, diplomats familiar with the situation said.

"I will do my best to let all ethnic leaders attend tomorrow's conference," said Suu Kyi. "It's their own decision whether they attend or not."

(Additional reporting by Aung Hla Tun and Aye Win Myint; Editing by Alex Richardson)