The head of the Citizens' Assembly has expressed disappointment after it emerged there was an issue with the recruitment of some replacement members for its most recent meeting.

The Citizens' Assembly has been meeting since October 2016, and has considered a number of topics - including issues such as the 8th amendment and climate change.

The Assembly consists of 99 citizen members, who are meant to be chosen at random to "represent the views of the people of Ireland, and will be broadly representative of society".

Seven replacement members were recruited for the weekend meeting of the assembly in January - which was focused on the manner in which referendums are held - but concerns were raised about the recruitment process.

RED C Research & Marketing, the firm involved in the recruitment, has confirmed that one employee acted outside of 'strict guidelines and protocols' when recruiting the seven people.

In a report, RED C explained: "The audit team were informed by the recruiter that family and friends had been asked if they knew of people who fit the criteria that may take part, and the interviewer then completed the survey over the phone with those people suggested by friends and family, instead of as required at random face to face."

The organisation has insisted that it 'stands over the integrity' of the rest of its work for the Citizens' Assembly in recent years, saying the recent issue was an isolated incident.

The seven members will no longer take part in the Assembly, and the Irish Independent reports that the recruiter in question has been suspended.

In a statement, Ms Justice Mary Laffoy - chair of the Citizens' Assembly - said she was satisfied that the discovery has no impact on the previous work done by the Assembly.

She said: "I am obviously disappointed that the Assembly finds itself in a position where these seven individuals, who were recruited in December 2017 and January 2018, have been recruited in a manner which is inconsistent with the agreed methodology.

"While this incident is regrettable, I believe that the actions which we have taken and will take to address the situation, ensure that the robustness of our work and the transparency and openness in which it has been conducted, can be maintained."

She added: "The Assembly has, at all times taken every aspect of its work with the upmost seriousness, including ensuring that its membership is representative of the population as reflected in the Census."

Details of the incident will be included in the Assembly's report to the Oireachtas on the manner in which referendums are held.

The full audit has been published on the Citizens' Assembly website.

The Assembly will meet next week to look at the prospect of fixed term parliaments, the final topic it has been asked to examine.