In a statement following a secret straw poll conducted on Monday by the UN Security Council, the ministry said Surakiart was still a "serious candidate" even though fewer than half the 15-member council cast a positive vote for his candidacy.

In a statement, the ministry argued the straw vote was not a popularity benchmark. It provided a rough indication only of whether a candidate had sufficient votes to continue their campaign.

South Korean Foreign Minister Ban Ki Moon and UN undersecretary-general for public affairs Shashi Tharoor from India received the most endorsements in the council's secret poll.

Ban received 12 "encouragements", one "discouragement" and two "no opinions". Tharoor followed with 10 encouragements, two discouragements and three no opinions. Surakiart received seven encouragements, three discouragements and five no opinions.

The ministry believed the combination of "encouragements" and "no opinions" made Surakiart a serious candidate.

It was now crucial to introduce the Association of Southeast Asian Nations (Asean) candidate to countries that remained undecided, according to the statement.

The straw poll came as a setback for the government, which claimed to have endorsement from more than 130 countries, including China.

Even though he did not receive the best score, it was such that Thailand and Asean would continue to campaign in the belief Surakiart had the qualifications and experience needed for the top UN post, the statement said.

On Monday, Asean foreign ministers endorsed Surakiart as its candidate in the face of growing competition.