BANGKOK -- Thailand expects to finish recertification of its major airlines by June ahead of a fresh International Civil Aviation Organization (ICAO) audit that it hopes will see it removed from the agency's blacklist after two years.

Thailand was red flagged by ICAO, an agency of the United Nations, in June 2015 over "significant safety concerns" that included lax inspections when granting air operator certificates. That led a number of countries, including Japan and the U.S., to bar Thai carriers from adding any new inbound services to their countries, and calls for Thailand to recertify its 28 international airlines.

Thai Transport Minister Arkhom Termpittayapaisiht

Thailand plans to ask ICAO for a new audit in June, but it could be one or two months before inspectors arrive, Transport Minister Arkhom Termpittayapaisiht told the Nikkei Asian Review.

Thai Airways International, the national flag-carrier, and Bangkok Airways, a private regional airline, should have completed recertification by then. Both airlines are currently in the fourth part of a five-stage program of test flights with inspectors on board.

In a separate interview with the Nikkei Asian Review, Puttipong Prasarttong-osoth, the president of Bangkok Airways, said test flights started last week and that his company expects to enter the final stage with actual recertification by February.

For Thai Airways, which has a wider variety of aircraft, the test flight phase will take longer, but Arkhom said he expects the flag-carrier will be recertified in time for the ICAO audit.

According to the ICAO website, only eight among about 190 member states have been flagged on safety grounds. These include Angola, Djibouti, and Nepal. Within the Association of Southeast Asian Nations (ASEAN), Thailand is the only country to be on the list following the upgrade of the Philippines in 2015.

In late 2015, the U.S. Federal Aviation Administration also downgraded Thailand to category two for failing to meet international standards. Indonesia had been stuck in category two since 2007 but was upgraded last August, leaving Thailand on its own from ASEAN.

Thailand hopes to rejoin its regional peers this year. Arkhom said recertification has been accelerated after the government decided to confine internal reporting and approval procedures to the transport ministry. The process historically involved the air force which had a large measure of control over Thai civil aviation. "I think we have made quite significant progress because now we have no interference from the military," said Arkhom.

Thailand has also been working on restructuring aviation oversight. Months after the ICAO red flag in 2015, the civil aviation department was dissolved into two organizations at ICAO's suggestion. This split civil aviation operators from regulators.