A lack of security and “rostering chaos” are leading to growing unrest among contact tracers in NSW, putting the vital public health measure at risk, the public service union is warning.

Many of the workers who interview infected residents and chase down COVID’s spread are not employed directly by the NSW government, the Public Service Association says.

Instead, they are engaged through ad-hoc labour hire arrangements with no job security.

The union says there is “growing rostering chaos”. It has heard reports of rising absenteeism, increased turnover and plummeting morale.

The union warns workers, many of whom are stood-down airline staffers, could soon quit.

“Insecure work and pandemics just don’t mix,” PSA Assistant General Secretary Troy Wright said in a statement.

“COVID-19 isn’t going anywhere, we need to make contact tracers permanent employees so that they’ll be there when we need them.”

NSW recorded no new cases of community transmission in the 24 hours to 8pm on Friday.

The state has gone nine days in a row without a local case after a scare earlier in the month.

But authorities still don’t know how a Sydney man in his 50s acquired the virus.

Vaccine efforts are ramping up with the state recording its highest number of jabs ever – 10,616 – in a single 24-hour period. More than 4000 of those were issued at the Sydney Olympic Park hub.