Current laws prevent child sex offenders across the country from working in businesses that provide direct services to children, such as childcare, tutoring or coaching.

But the bill passed in SA's lower house on Tuesday goes a step further, preventing registered child sex offenders - as well as those charged and on bail - from taking any job in a business where they would be in contact with underage employees.

The state is the first in the country to impose such a blanket ban, amending a "clearly unacceptable" situation, SA Attorney-General Kyam Maher said.

"I'm pleased to see this supported by all sides of parliament, which will better protect our children and young people," he said.

Independent upper house MLC Connie Bonaros was a strident advocate for the law, saying parents would be outraged if they were aware of the "loophole" in the legislation.

"I can only imagine the 'pit in the stomach' feeling and fear parents have had to endure seeing a convicted sex offender on the news, knowing that person worked alongside their child and there was nothing in the law to prevent it, let alone advise them of that," she told parliament in February.

Shop, Distribution and Allied Employees' Association secretary Josh Peak said it was a common-sense reform that would better protect young workers across retail, hospitality, fast food and other industries.

"Child sex offenders have no place working with or managing young people in any setting," he said.

"There have been far too many incidents where managers charged with child sex offences have been allowed to continue working alongside young workers in retail and fast food.

"Young retail and fast food workers - and their parents - can rest easy knowing there are now protections in place to keep child sex offenders out of their workplaces."

1800 RESPECT (1800 737 732)

National Sexual Abuse and Redress Support Service 1800 211 028

Australian Associated Press