BANGKOK (Reuters) -Thailand on Monday justified hosting talks aimed at re-engaging with Myanmar's shunned military, saying dialogue was necessary to protect its border with the strife-torn country, even as key Southeast Asian neighbours stayed away.

Myanmar's generals have been barred from high-level meetings of the 10-member Association of Southeast Nations (ASEAN) since they seized power in a 2021 coup and unleashed violence on those who challenged their takeover.

But Thailand's outgoing military-backed government invited ASEAN foreign ministers, including the one appointed by Myanmar's junta, to discuss a proposal for the bloc to "fully re-engage Myanmar at the leaders' level", according to an invitation seen by Reuters and verified by sources.

Critics see the meeting as undermining a unified ASEAN approach to the crisis in Myanmar but Thai Prime Minister Prayuth Chan-ocha said talks were necessary to protect his country, which shares a long border with Myanmar.

"We suffer more than others because Thailand has more than 3,000-km shared land border as well as a maritime border," Prayuth told reporters. "That is why the talks are necessary. It is not about taking sides."

Thailand's foreign minister, Don Pramudwinai, said earlier that Myanmar's crisis was sending refugees across the border into Thailand and it had hit trade hard.

"We can say that Thailand is the only country in ASEAN that wants to see the problems end as soon as possible," he told broadcaster Thai PBS.

He said other ASEAN countries "should be thanking us for doing something to help support their main goal".

Myanmar's junta-appointed foreign minister, Than Swe, was due to join the talks, two sources with knowledge of the meeting told Reuters.

But some ASEAN members declined to attend in a clear indication of their disapproval, while others sent junior officials.

Indonesia, which as the current ASEAN chair has for months been trying to engage key stakeholders in Myanmar's conflict in an effort to kick-start a peace process, did not join the talks.

Its foreign minister, Retno Marsudi, said ASEAN had "arrived at no consensus to re-engage or develop new approaches to the Myanmar issue", according to a letter seen by Reuters and verified by a source.

'BETRAYAL'

The military took over in Myanmar in 1962 and suppressed all opposition for decades until it launched a tentative opening up in 2011. But its experiment with democracy, which included elections swept by Nobel Peace Prize laureate Aung San Suu Kyi, came to end when the military ousted her government, reimposed strict military rule and crushed protests.

With Myanmar again drawing Western condemnation and sanctions, ASEAN drew up a five-point plan, including an end to violence, dialogue and humanitarian assistance, but Myanmar's generals have ignored ASEAN's effort to the increasing frustration of the bloc.

Malaysia's foreign minister also declined to attend the talks in Thailand, his ministry said in a statement, adding that it was important for ASEAN to demonstrate unity in support of Indonesia's effort.

Singapore's foreign minister, Vivian Balakrishnan, told a press conference in Singapore with his U.S. counterpart last week that it was "premature to re-engage with the junta" at a high level. It was not immediately clear on Monday if an official from Singapore was attending the talks in Thailand.

Cambodia said Foreign Minister Prak Sokhonn, who last year served as an ASEAN special envoy to Myanmar, would be represented by his deputy. It had said on Friday Prak Sokhonn would lead the Cambodian delegation.

An organisation of Southeast Asian lawmakers, ASEAN Parliamentarians for Human Rights, called the talks a "betrayal of the Myanmar people and an affront to ASEAN unity".

(Reporting by Panu Wongcha-um in Bangkok, Ananda Teresia in Jakarta, Rozanna Latiff in Kuala Lumpur; Writing by Kanupriya Kapoor; Editing by Kay Johnson, Robert Birsel)