Thailand's new Prime Minister Srettha Thavisin will miss a regional meeting of Asia's leaders in Jakarta next week, the foreign ministry said on Sunday.
Srettha won a parliamentary vote to become prime minister last month and his cabinet was endorsed by the king on Saturday.
The prime minister and his cabinet are due to take an oath before an audience with King Maha Vajiralongkorn on Tuesday and will then deliver a policy address in parliament. They can then officially carry out their duties.
Permanent secretary Sarun Charoensuwan will represent Thailand at the Association of Southeast Asia Nation (Asean) Summit, the Ministry of Foreign Affairs said in a statement. It did not say specifically why the prime minister was not attending.