The escalating crisis in Myanmar was set to dominate summit talks on Friday between Southeast Asian leaders struggling to find a way to calm the bloodshed in the junta-ruled country.

Leaders from the Association of Southeast Asian Nations (Asean) regional bloc will discuss ways to implement a peace plan agreed with Myanmar last year which the junta has so far ignored.

Myanmar has spiralled into bloody conflict since the military ousted Aung San Suu Kyi's civilian government in February last year, with thousands killed in clashes since.

There is growing frustration among the other nine Asean countries at the generals' foot-dragging on the so-called "five-point consensus" but so far no concrete plan to enforce it.

President Ferdinand Marcos Jr of the Philippines called for "patience" in resolving the crisis at talks with Cambodian premier Hun Sen, the summit host.

Asean has blocked junta chief Min Aung Hlaing from attending the gathering in Phnom Penh, which US President Joe Biden will join on Saturday.

Biden will then go on to hold a high-stakes meeting with his Chinese counterpart Xi Jinping on the sidelines of the G20 summit in Indonesia on Monday.

Premier Li Keqiang will hold talks with Asean leaders on Friday afternoon, before joining Biden and other regional leaders for an East Asia Summit in Phnom Penh on Sunday.

Western powers have heaped sanctions on the junta and the United States has urged Asean to take a "forceful" stance to squeeze the junta to reduce the violence, which escalated in recent weeks with deadly military air strikes on civilian targets, including a school and concert.

Daniel Kritenbrink, the top US diplomat for East Asia, said Myanmar would be a top subject when Biden meets Asean leaders on Saturday.

Within the bloc, Indonesia, Malaysia and Singapore have led a push for tougher action.

Earlier this month Singapore's Foreign Minister Vivian Balakrishnan warned that the Myanmar military had "a very high tolerance for pain, very high tolerance for isolation" and the crisis could take decades to resolve. (AFP)