Key stakeholders are meeting in Tonga today over the controversial Chinese plane that prompted New Zealand's foreign minister to suspend tourism funds and issue a travel warning.
An unfavourable transport report from the World Bank has prompted Tonga to ask for time to respond.
The report says the aircraft was not certified properly and should be grounded, and the Tonga Civil Aviation Act is outdated.
The report was commissioned by the prime minister, Lord Tu'ivakano, and Murray McCully in March.
Mr McCully disputes the proper certification of the MA-60 aircraft, but Tonga's deputy Prime Minister, Samiu Vaipulu, says it was done in accordance with the rules of the International Civil Aviation Organisation, as well as China, with whom Tonga has an aviation treaty.
Earlier this month Mr Vaipulu criticised the World Bank for not contacting him while compiling the report.
A New Zealand pilot, Rodger McCutcheon, has offered a way to re-certify the plane, with New Zealand pilots test-flying it.