Australian economist Sean Turnell remains in detention in Myanmar as Cambodian Prime Minister Hun Sen apologised for suggesting the former adviser to ousted leader Aung San Suu Kyi had been freed.
Prof Turnell has been detained for a year after his arrest following last year's February 1 coup.
He has been charged with violating Myanmar's immigration and official secrets acts by trying to leave the country with sensitive financial information and is facing a 14 year jail term.
Hun Sen was on Monday quoted by the Cambodian official Agence Kampuchea Presse news agency as saying he welcomed Prof Turnell's release by Myanmar junta leader Aung Min Hlaing, which followed his request on behalf of Australia.
The Fresh News service reported Hun Sen also said: "The release is indeed to the senior general's credit, but at least I also contributed as the rotating chair of ASEAN".
But the Cambodian prime minister issued a statement later in the day saying he had been mistaken.
"In reality, the Australian national was not released," Hun Sen said in a Facebook post late on Monday.
"The confusion is because of me getting information wrong, please forgive me for unintentional mistake".
A Department of Foreign Affairs and Trade spokesperson told AAP in a statement on Monday night that Myanmar authorities had advised DFAT that "Professor Sean Turnell remains detained".
The statement added: "The Australian government repeats its call for Professor Turnell's immediate release, and for his rights and welfare to be upheld".
Pressure has been mounting on the junta to release Prof Turnell since Hun Sen became the first leader to visit Myanmar since the coup in an attempt to move an ASEAN-backed Five-Point Consensus forward.
"Professor Turnell's detention is unjust, and we reject the allegations against him," Australian Foreign Minister Marise Payne said in a statement on Sunday.
Myanmar military spokesman Zaw Min Tun earlier told BBC Burmese there were no plans to release Turnell and Myanmar Foreign Affairs Ministry officials told the EFE news agency that he remained detained.
Turnell's trial has yet to start.
He is among about 11,000 people detained since the coup, activists say.
with reporting from AAP, Reuters and EFE
