President Thein Sein has made a wide-ranging peace deal atop priority, and the failure to bring more armed ethnic groups together is a blow to the ruling Union Solidarity and Development Party ahead of a Nov. 8 general election.
One group which has continued to hold out is the Kachin Independence Organisation, which controls vast areas of Kachin State. As recently as this week its armed wing clashed with government troops in the northeast.
Peace talks have dragged on for over two years. The latest round of negotiations, among 19 groups, was held in Chiang Maiin Thailand and ended on Wednesday.
Min Zaw Oo, an official at the government-linked MyanmarPeace Center, which coordinates the talks, said he expected between seven and nine groups to sign a ceasefire agreement following another meeting between parties on Saturday in Yangon.
He added that other groups would not be barred from joining at a later date. "The NCA (nationwide ceasefire agreement) is an open book," he said.
Some ethnic organisations agree to the draft text of the agreement in principle but are holding out because they want the Arakan Army (AA), Ta'ang National Liberation Army (TNLA) and Myanmar National Democratic Alliance Army (MNDAA) to be allowed to sign the ceasefire.
Thein Sein's administration has rejected this request because the three do not have existing bilateral ceasefire agreements with the government.
The AA and TNLA helped the MNDAA, led by ethnic Chinese commander Peng Jiasheng, fight against the Myanmar military in the Kokang area earlier this year.