LABUAN BAJO, May 10 (Reuters) - Southeast Asian leaders meeting in Indonesia will on Wednesday wrangle over an escalating crisis in military-ruled Myanmar, with patience in the ASEAN bloc wearing thin as its junta shows no intent to end hostilities and pursue a peace plan.

The summit of the Association of Southeast Asian Nations (ASEAN) takes place as Myanmar's military intensifies attacks and air strikes on resistance forces and ethnic minority rebels as it tries to consolidate power ahead of a planned election.

It also comes days after a unknown assailants shot at a convoy of regional diplomats and aid workers in Myanmar bringing supplies to some of the more than 1 million people displaced by conflict since a 2021 coup.

Indonesian President Joko Widodo, the current ASEAN chair, called on the 10-country bloc to speak up and speak as one on its most challenging issues.

"Will ASEAN only be silent or will ASEAN be able to become the driver or peace or growth?", he said in a speech ahead of a meeting set to also discuss regional tensions and a code of conduct for the South China Sea.

"I am convinced that we all believe ASEAN can do it only if there's unity."

The prime minister of East Timor, a former Portuguese colony bordering Indonesia that is seeking ASEAN membership, stressed the need to restore order in Myanmar.

"We also have the obligation to push ASEAN and the international community to create peace in Myanmar," Taur Matan Ruak said.

ASEAN, which has a policy of non-interference in its members affairs, has become increasing assertive with Myanmar's junta over its failure to implement a five-point peace "consensus" that its top general agreed to with ASEAN a few month after his coup sparked chaos.

ASEAN has barred the generals from high-level meetings until they execute the peace plan, which includes ceasing hostilities, starting dialogue and allowing full humanitarian access.

Indonesia has also been quietly engaging Myanmar's military, its shadow government and armed ethnic groups to try to kick-start peace talks.

"ASEAN is doing as much as it can really because when you are there on the ground it's not that easy," Philippine foreign minister Enrique Manalo said.

But some have called on ASEAN to take a harder line with Myanmar's junta.

"To leave the seat empty at ASEAN summits is actually their comfort zone, they don't have to be held accountable," said former Indonesian foreign minister Marty Natalegawa.

"Excluding the junta is only part of a series of steps that should be taken."

He said the schism over Myanmar presents an "unprecedented challenge" to the bloc's unity and it was essentially functioning with only nine of its 10 members.