A law change is needed to prevent security guards being at risk of facing assault charges for doing their jobs, the New Zealand Security Association (NZSA) says.
Under the Crimes Act, a guard could be prosecuted for chasing a robber down the pavement and tackling them to the ground.
NZSA chief executive Gary Morrison said it was having discussions with the police minister about updating the legislation, as there were about 30,000 licensed security guards throughout the country.
Morrison said they were not keeping up with the increasing demand and at times there were more than 500 vacancies.
He said that demand was coming from a wide range of businesses, including hospitality, retailers, health care providers and commercial premises.
Morrison said some people were put off applying to be a security guard as it was not well paid, and they felt unsafe and unable to protect themselves on the job.
"We have certain rights under the Crimes Act 1961, but its poorly worded legislation and it leaves doubt about whether they are allowed to use force or restrain an offender."
He said the NZSA had already had discussions with the police minister about the outdated legislation and will be meeting with him again in a couple of weeks.
"We need to be able to make it clear in what circumstances security guards can detain offenders, and not."
Morrison would like security guards to have access to more backup from police, if they were called when a situation becomes dangerous.
"We are also getting more work as police have moved away from traditional policing areas. Some regions struggle more than others to get police to help if they need assistance. It's an ongoing battle as its up to the number of police and their own priorities. It's obvious they are struggling with resources.
"We are continuing positive discussions with the minister and all of us want to make the country safe."
Police Minister Mark Mitchell said the issue was raised in discussions he was having with "security stakeholders" to identify "whether there are additional powers we can look into to support the sector".