Secure Porirua facilities housing some of New Zealand's most dangerous mental health patients have had "serious concerns" raised about their security systems.
Capital & Coast District Health Board's forensic Purehurehu and Tawhirimatea mental health units at Kenepuru currently have 45 patients and 107 staff.
Public Service Association national secretary Glenn Barclay confirmed the union had raised its "serious concerns" with the health board, "with a view to urgent maintenance to ensure our members' safety".
"We understand the system is separate to the ones operating in other CCDHB facilities and that it is nearing the end of its life."
The health board's addiction and intellectual disability services general manager, Nigel Fairley, says security systems at forensic units at Kenepuru were "functioning and operating as they should to ensure safety and security".
He said security systems were upgraded and enhanced in 2016 and 2017, and renovations and the build of the new acute wing at Purehurehu were now "well underway".