A Perth mother was told her 10-week-old son would need a $100 ticket to enter a Paul Kelly concert in Kings Park on Saturday night.

The 31-year-old, who asked not to be named, said she was shocked as most venues had no issue with breastfeeding mothers bringing babies.

The woman was also told there would be strictly no pass outs at the event and she would not be allowed back in if she left to feed her son.

"I was pretty shocked, it's not as if he can listen or watch the concert," she said.

"We're not taking up a reserved seat or anything, we're sitting on the grass on a picnic rug at Kings Park".

She said she would understand if it was a busier concert but the event was advertised as a sit-down show with patrons encouraged to bring picnic rugs and low-deck chairs.

"Kids over one and older, fair enough, I totally understand that," she said.

"But it didn't occur to me that a babe in arms that was still breastfeeding, especially a 10-week-old, had to have a $100 ticket."

A long-time Paul Kelly fan, the woman said she had been looking forward to the concert after getting tickets as a gift.

"I thought my husband and I would be able to go as our first night out since the bub was born," she said.

"We thought it would be an easy event to be able to go to together without any issues."

The couple had ordered their son special baby ear muffs and a mosquito net for the event.

"That's all now wasted money on top of now not knowing if I'll be able to attend," the woman said.

"Infants fly free on most airlines and breastfeeding is even allowed in parliament."

'Event not suitable for children'

Mellen Events, the company running the concert, was contacted for comment.

The company's Babes In Arms and Minors Policy cites the number of people attending, the lack of light, loud music and light effects as potential concerns for infants attending events.

They also cite the potential for crying babies to disturb other patrons.

"The promoters do not consider this event suitable for children under the age of two years. A children's priced ticket will be available if the promoter considers the event family orientated/friendly," it read.

"As the safety of children, parents and all patrons is of paramount importance to us, these concerns are brought to your attention for your consideration, so that you, your family and all other patrons can enjoy the show in a safe and comfortable environment."

Despite these concerns the event is left open for children of any age to attend, as long as they have a full price ticket and a guardian present.

The mother was offered a refund for her ticket at 2:00pm on Saturday but was told she must claim it before 3:00pm.