The government has made ending over half a century of civil strife in the country's minority border areas a key priority as the nation emerges from decades of junta rule.
But talks have been hampered by lingering mistrust and pockets of tension in several minority areas.
"Everyone accepts that Myanmar's peace process is at a very crucial moment," Aung Min, a former general at the forefront of the peace efforts, said opening the latest round of talks which are due to run for several days.
"Because of efforts from both sides, we have agreed on many facts... We have made progress never before seen in Myanmar's history," said Aung Min, noting that the government had agreed to accept the concept of federalism in the peace process - a key demand of minority groups.
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But he acknowledged that the process has taken much longer than expected.
Ethnically diverse Myanmar has suffered the world's longest-running civil war with multiple insurgencies in its resource-rich borderlands that flared soon after independence from British colonial rule in 1948.
A quasi-civilian regime that took power in 2011 has signed ceasefires with 14 of the 16 major armed ethnic groups, but deals with the Kachin Independence Army (KIA) and Ta'ang National Liberation Army (TNLA) in Shan State have so far proved elusive.
Around 100,000 people have been displaced by sporadic fighting between the KIA and government forces that broke out in June 2011, soon after the new government replaced junta rule.
Myanmar's army is present at the latest round of talks - seen as an important step to agreeing a binding deal.
The rebel negotiators, who are pushing for swift political dialogue in exchange for laying down their weapons, highlighted the importance of reaching a deal.
"If we continue like this, there's no hope for our country, it could eventually split into pieces," said Naing Han Tha, who led the ethnic group negotiators.
"The destiny of our people depends on us.