Associate Professor Michelle Giles authorised the latest suite of restrictions last month, including extending the now scrapped 9pm to 5am curfew that is being challenged in Victoria's Supreme Court.

"I knew these decisions would have impacts on people, I've never pretended otherwise but my role was ... to protect public health, to protect people from coronavirus," she told the Supreme Court on Thursday.

The validity of the curfew is being challenged by cafe owner and aspiring Liberal MP Michelle Loielo, who claims it violated her human rights and caused strain on her mental health.

In court documents, she claimed even though the curfew was scrapped from last Monday morning, she lives in fear it will be reinstated.

"Every time I see the premier, Daniel Andrews on the television and every time I hear the premier speak, I feel a sense of dread and anxiety," she said.

"I feel this way because I am insecure about whether he is going to reimpose the curfew, simply because he has the power to do so."

The curfew was introduced as part of stage four restrictions in early August, and extended by Prof Giles on September 13.

She said the directions she signed off on were developed by public health teams and approved by Chief Health Officer Brett Sutton before being passed to her for authorisation.

Prof Giles authorised the directives late on the Sunday night, about 12 hours after they were announced by Mr Andrews at a press conference.

Ms Loielo's barrister Marcus Clarke QC accused Prof Giles of being "dictated to" by Mr Andrews.

She rejected that allegation and said she could have refused to authorise any of the directives, and said she considered removing the curfew.

"What I was most worried about was the risk that if I removed those restrictions too early or too quickly - we were at a really precarious point still having 40 to 70 infections a day - and I didn't want to make a decision to cause that to go up," she said.

Prof Giles said there was no evidence to support the curfew in isolation, but it was backed by evidence as part of a package of restrictions.

She said she had considered a range of impacts the curfew would have on people, including on finances, mental health and for people in domestic violence situations.

"I wish I could do that without having any of those other negative impacts ... but I just can't see how we could bring the coronavirus pandemic under control without making these difficult decisions," she said.

Ms Loielo said she felt as if a part of her life had been given back to her after the curfew was scrapped.

The trial will continue on Friday.

Australian Associated Press