The Future Forward Party (FFP) said on Monday international organisations and embassies sought permission to observe party leader Thanathorn Juangroongruangkit when he reported to the police on Saturday to face charges involving a pro-democracy rally he attended four years ago.
The party was responding to a remark by Foreign Ministry spokeswoman Busadee Santipitaks, who told the media on Sunday she had information claiming the international bodies had been invited to the event.
"Did we invite them? Well, I have to say that if those embassies weren't really interested in this matter, they would not have come, invited or not," FFP spokeswoman Pannika Wanich said.
"The United Nations [official] telephoned us saying they would like to attend, and that they had sent a letter informing the Pathumwan police station of this," she said.
"Did we contact the embassies before and were we aware they would come on Saturday? Yes, we knew because we had to check [who would come] so we could assign someone to take care of them," she noted.
"But once again, according to diplomatic tradition they would not have come if they had not been interested in the issue. So it doesn't really matter if anyone invited them or not," she added.
On Saturday, diplomats from Australia, Belgium, Canada, Finland, France, Germany, the Netherlands, the UK and the US, as well as EU and UN human rights officials, went to the station as observers.
Mr Thanathorn was charged with sedition under Section 116 of the Criminal Code, helping a suspect escape under Section 189, and organising an assembly of more than 10 people that caused unrest (Section 215). If convicted, he could face respective jail terms of seven years, two years and six months for the three charges.
He denied the charges and said he would provide written testimony on May 15.
Ms Busadee said the ministry will supply those diplomats with facts about the Thanathorn case.
The National Council for Peace and Order (NCPO), meanwhile, denied an accusation by Amnesty International Thailand that it was trying to silence Mr Thanathorn.
Col Sirichan Ngathong, a deputy spokesperson for the NCPO, said Mr Thanathorn would be granted the same rights as all other suspects.
Mr Thanathorn's case will likely be handled by the Military Court, which deals with offences fitting the four categories of security cases committed between 2014 and 2015 when the NCPO seized power.
