South Australia is one step closer to decriminalising sex work, with a bill passing the Legislative Council overnight.

Debate on the bill stretched late into the night, with Labor MP Tung Ngo introducing eight amendments at the eleventh hour.

Those amendments included banning sex workers from soliciting on the street and banning brothels from setting up near childcare centres, schools and places of worship.

Mr Ngo argued Parliament should have more time to consider his amendments.

"My amendments are pretty straightforward, pretty practical and I think honourable members need more time to think it through," he said.

"If honourable members believe it is not OK to allow streetwalkers operating outside of people's homes, then support me. Make it illegal."

All Mr Ngo's amendments were voted down, with the bill eventually passing with a conscience vote, 13 to eight.

Late amendments frustrate members

Liberal MP Michelle Lensink introduced the legislation and said there was some frustration with the late amendments.

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"It's certainly not ideal for members of the parliament to put amendments to bills late," she said.

"It's not well regarded by most people. It's a pretty poor practice because it places everyone else under stress in terms of formulating a position."

Earlier in the evening, Australian Conservative MLC Robert Brokenshire tried to have the vote delayed.

He said he had more than 1,000 constituents waiting for an update on the progress of the bill, and he hadn't been given enough time to digest Mr Ngo's amendments.

"I want to do due diligence on it and the fact is that I have had no chance to consider the plethora of amendments of the honourable Tung Ngo," Mr Brokenshire said.

"I've certainly no chance to then consult with the constituents that I deal with under the democratic process."

Restrictive laws make workers feel unsafe

In March, a select committee recommended the bill continue through the Parliament without amendment.

Ms Lensink said the bill's success in the Upper House is likely to help sex workers feel safer.

"South Australia has the most restrictive laws in Australia and what that means is that they're difficult to police," she said.

"I think that helps a lot of the people who were working in the industry who were made to feel unsafe to assist them in going forward."

The bill will now go before the Lower House where MPs will also be able to cast a conscience vote.

Laws vary across the country, but New South Wales is the only state in Australia to have completely decriminalised sex work.