WASHINGTON, March 18 (Reuters) - The White House said on Thursday (Mar 17) it is discussing new dates for a Washington summit with the Association of Southeast Asian Nations after ASEAN chair Cambodia said it had been postponed because not all leaders could attend later this month.

The White House announced last month that US President Joe Biden would play host to a special summit with ASEAN on Mar 28 and 29.

Asked about the Cambodian foreign minister's announcement of a postponement earlier this month, a spokesperson for the White House National Security Council said Biden looked forward to welcoming the ASEAN leaders to Washington.

"To ensure invited ASEAN leaders can all participate, we are working closely with ASEAN partners to identify appropriate dates for this meeting," the spokesperson added.

Cambodian Foreign Minister Prak Sokhonn said the meeting had been postponed because some ASEAN leaders could not attend on the proposed dates.

The summit is seen as part of US efforts to step up engagement with a region Washington sees as critical to its efforts to push back against China's growing power. It had been expected earlier in the year, but was delayed by COVID-19 concerns.

The White House has described the summit as "a top priority" and said it would commemorate 45 years of US-ASEAN relations.

It has said it will follow ASEAN's lead by inviting a non-political representative from military-ruled Myanmar.

The bloc has barred the Myanmar junta from key meetings since last year over its failure to honor an agreement to end hostilities in the country that have killed hundreds of civilians and displaced more than 300,000.