The ECT says that overseas voting ballots from New Zealand did not arrived in time, and that they will be deciding tomorrow (26 March) whether these ballots are invalid. 

Nath Laoseesawakool, Deputy Secretary-General of the Election Commission of Thailand (ECT) said earlier yesterday (24 March) that some overseas ballots had just arrived in Thailand that morning, following a flight delay. The ECT said they could not reveal which country the ballots were from and how many are there, but if they are not delivered in time, they could become invalid.

ECT Secretary-General Jarungvith Phumma said in a press conference at 21:27 that the ballots were delivered from Wellington to Auckland by an Air New Zealand flight, and handed over to Thai Airways on 21 March. The ECT has investigated and found that the ballots were stuck in Auckland before arriving in Thailand during the night of 23 March. As of the press conference, the ballots were still being stored by Thai Airways.

The press release from the Thai Embassy in Wellington

Meanwhile, earlier this morning (25 March), the Thai Embassy in Wellington issued a press release saying that the ballots left Wellington by air cargo on 18 March and should have arrived in Thailand on 19 March. However, the Embassy said that the delivery process is not under its control.

“The Embassy understands the feeling of every voter, and we feel very disappointed and sad that our voices and the voice of Thai voters in New Zealand are not reflected in this election, even if all of us, including election organization volunteers, have been preparing for this election together for over two months, in the hope that there will be no obstacles to overseas voting in New Zealand.”

Overseas voting ballots have to be delivered to their respective constituencies by 17.00, when the polls closed and counting begins.

The ECT said in today's press conference (25 March) that the ECT will make a decision tomorrow whether the ballots from New Zealand are invalid.          

According to Matichon, 1,500 ballots or one-third of all votes from New Zealand may be invalid. The Embassy’s press release says that 1862 voters registered in New Zealand. 1542 people voted, or 82.81% of all registered voters.

At 17.20, Khaosod English reported that Thai Airways International President Sumet Damrongchaitham said that the ballots were delivered on time. According to Sumet, the ballots were shipped from Auckland on 22 March and arrived in Bangkok at 20.50 on 23 March. He said that airline staff contacted the Ministry of Foreign Affairs on 23 March to retrieve the ballots between 22.00 and 22.30, but they were picked up at 19.30 the next day.     

Update (26 March) : 

at 16.53, iLaw reported that the ECT has ruled that all ballots from New Zealand are invalid, since they were not delivered to their respectively constituencies within the timeframe specified by Article 114 in the Organic Law on the Election of MPs.