The continued use of police cells to hold immigration detainees in Northern Ireland must be explained, members of the Policing Board have insisted.
The board's Human Rights and Professional Standards (HRPS) committee has asked why police stations were still being used when the UK Border Agency has established its own holding facility in Larne.
Members highlighted that in the nine months after the UKBA centre was opened, 146 immigration detainees were held by the PSNI.
People detained in Northern Ireland for immigration purposes are often transferred to large UKBA centres in Scotland and England. As the detainees have not been charged with a criminal offence, the centres are designed to provide a relaxed setting.
The UKBA centre in Larne is a short-term facility used to accommodate detainees before they are transferred. Prior to its opening in July 2011, PSNI custody suites were used for the same purpose.
In its annual report, the board's HRPS committee said it was not clear why police custody was still being used since the centre opened.
Committee chair Conall McDevitt said: "Whilst the number of immigration detainees held in police custody during 2011/2012 decreased compared to the previous year, there were still 146 detainees held in police custody from 1 July 2011 - 31 March 2012.
"Given that the short term holding facility in Larne was open during that period, the Board has asked PSNI to explain why UKBA are continuing to rely on the use of police custody for immigration detainees."
The request for an explanation was one of 11 recommendations made in the report. Among other issues examined by the board was the PSNI's approach to handling public order situations. The latest report only focused on the period up to September last year and did not assess the PSNI's handling of the current flag related violence. As a consequence, members have commissioned the board's human rights adviser Alyson Kilpatrick to undertake a more comprehensive analysis of public order incidents.
In response to the findings, PSNI Assistant Chief Constable George Hamilton said: "Accountability on this important issue is essential and PSNI welcome the scrutiny provided through the Board's Human Rights Committee and the work of their human rights adviser. The launch of the Human Rights Annual Report presents a welcome opportunity to have a public conversation on the issues that matter most to communities."