The decision to "promote" Valletta 2018 chairman Jason Micallef was profoundly disturbing, an international writers' organisation said, as it chastised the Prime Minister for failing to stick to his promise.

In an open letter to Joseph Muscat, PEN International said it had received assurances that Mr Micallef's controversial comments on Daphne Caruana Galizia would be seriously considered during a meeting they had held with the Prime Minister last October. 

Joseph Muscat had told members he would consider calling for Mr Micallef's resignation, according to PEN.

The organisation said Dr Muscat had stated, on the record, that he had held "serious conversations" with Mr Micallef following his incendiary statements on Ms Caruana Galizia, with which he said he disagreed.

"You went on to say that you understood PEN’s protest and the outcry generated by Mr Micallef’s behaviour and that you would consider calling for his resignation as chair of Valletta 2018," the organisation said in their letter.

Mr Micallef had sparked anger among several local and international artists after uploading a social media post mimicking the slain journalist's last words. He had also vehemently opposed the memorial for the journalist and had removed banners calling for justice in her murder.

However, rather than censuring Mr Micallef, the Maltese authorities have promoted him to oversee a key cultural agency, the organisation told the Prime Minister. 

Culture Minister Owen Bonnici confirmed on Thursday Mr Micallef would chair the Valletta Cultural Agency after the city's stint as European Capital of Culture comes to an end on December 15.

The international organisation called on the Prime Minister to reconsider Mr Micallef's position, noting it was completely at odds with the concerns expressed during their meeting.

"We are profoundly disturbed by what appears to be a total lack of accountability from the Maltese authorities with regard to the extremely serious allegations made by PEN International and a wide range of leading international cultural actors," the letter read.