Anti-abortion activist Joanna Howe has been banned from parts of South Australia's upper house, with parliament told she allegedly insulted, intimidated and threatened MPs on the night of a vote about late-term abortion law.

Dr Howe has hit back at the ban, calling it a "total abuse of power" which she would "strongly contest going forward".

She also refuted "every allegation that has been made".

This week, Liberal politician Jing Lee revealed she felt unsafe and had been put in a compromised position after an encounter with an "external visitor" who made her feel "very vulnerable on the night" of a vote about proposed amendments to abortion laws.

Upper house president Terry Stephens identified the external visitor as Dr Howe, who is a legal professor at the University of Adelaide, and who helped draft the proposed changes.

Mr Stephens said he had received multiple complaints from members of parliament about her behaviour in the galleries and areas adjacent to the Legislative Council chamber.

"It was claimed Dr Howe was observed yelling at the honourable Dennis Hood to discourage him from vacating the chamber in order to provide a pair for the vote."

Mr Hood agreed to enter a pairing arrangement with Michelle Lensink after Ms Lee reneged on her own arrangement with her Liberal colleague.

Dr Howe has previously said she was not "100 per cent certain" she was the external visitor Ms Lee had been referring to, but had admitted to lobbying her on the night of the vote.

She told ABC Radio Adelaide on Thursday that "no formal complaint or allegation has actually been put to me".

"I have been denied both procedural and substantive fairness in this case," she said.

"I have never been identified as the person [Ms Lee] spoke about and I strongly refute that framing that was given."

In parliament, Mr Stephens said he had been provided with further accounts from other members who allegedly witnessed Dr Howe in the corridors and adjacent areas.

"Members have claimed to have witnessed insults and threatening and intimidating tactics employed by Dr Howe towards some members," he said.

"It is even more unacceptable that any member should feel intimidated or threatened by visitors while carrying out their free performance as a member of the council."

Mr Stephens said MPs should "feel safe in carrying out their parliamentary duties and have confidence that they are free to do so without interference".

"In considering these accounts, I have decided that Dr Howe behaved in a manner that did not afford members that right and risked compromising the effective functioning of the chamber," he said.

Mr Stephens banned Dr Howe from the upper house, including the public and president's galleries, and areas adjacent to the chamber, such as the corridors and other shared spaces.

He reminded MPs they must take responsibility for their guests.

Dr Howe said the ban was an "appalling" abuse of power.

"It's an affront to Australian democracy — the thought that a member of the public could be banned from the people's house because a cabal of pro-abortion MPs in the parliament have made anonymous complaints to the president," she said.

"This is an unprecedented, shocking decision.

"I know most South Australians, even if they disagree with me on abortion, would be absolutely shocked that a member of the public and an advocate was banned from parliament on the flimsiest of grounds."

Liberal MP Ben Hood, who introduced the bill seeking to change the state's abortion laws, walked out of the chamber as Mr Stephens began his statement.