When the issue of childcare arrangements was raised, Ms Sleep said, she was not satisfied the woman had the right plans in place, such as extended family and friends who could provide extra care.
"I thought, 'Oh dear, this particular employer would not be happy if I considered your application based on [this]'. What I am saying is that kids, no problem, but you better have a plan B because every mother knows that daycare is a hotbed of disease and infection.
"I didn't turn her away. What I said was, 'Come back to me when you have sorted out a plan B for the kids and I am more than happy to move this forward'."
The employer had had a "bad experience" with a previous employee who took too much time off to care for sick children, Ms Sleep said.
"It's risk management and clients don't pay us a handsome fee to send them risky candidates. The candidates don't pay us a brass razoo. In business you work for the people who pay you.
"[The mother] thought that if her kids got sick it was her right under the law to take time off to look after her kids and if it was in excess of those five days [sick leave] then it was her right and an employer should come to the party."
Asked if she considered her advice discriminatory, Ms Sleep replied: "I call that business ... I hope she went away and gave it some thought ... I got the distinct impression she was not listening at all."
Employment lawyer Penny Swarbrick said it was unlawful to assume children would be a problem for an employee. "The question should be, 'Is there anything preventing you from being able to attend work regularly'."
Discriminating against a person on the basis of their family status, which included their need to care for children or their gender, was in breach of the Human Rights Act, and potential employees having children should not be of interest to any employer, she said.
Ms Swarbrick said a person should be able to turn up at work to fulfil their part of an employment contract.
"But how they do that, and their domestic arrangements, is entirely over to the employee."
Even if the recruitment agent was not the employer, Ms Swarbrick said they could be in breach of the act by preventing people from getting employment on childcare grounds.
However Ms Sleep did not think it was unfair to assume someone would need more sick leave because they had children. "If they don't get sick then that's just good luck."
Ms Sleep said she hired a lot of mothers and also asked men the same questions about childcare arrangements.
"Mothers returning to the workforce are great because they are very organised and know how to multitask."