The woman, named by The Courier-Mail as Debra Pettigrove, and the boy were flying from Brisbane to Denpasar six months ago when he told her his drink — a double gin and squash — “tastes yuck”.

Ms Pettigrove’s grandson has plant allergies and she says he reacted to the drink with hay fever, watering eyes, sneezing and headache.

Shine Lawyers is representing Ms Pettigrove.

In a brief given to AAP by the firm, it’s claimed Ms Pettigrove wants Jetstar to “at least offer a full trip somewhere to supplement such a horrific experience”. Jetstar have already offered Ms Pettigrove and her family $400 in flight vouchers as compensation.

The airline says the mixer mix-up happened when similar-looking drinks from an adult customer and the boy were taken to the galley during turbulence to prevent spillage.

When the drinks were returned the adult passenger was asked to taste and confirm if he’d been given the correct drink.

After confirming that he had the right drink, the other beverage was given to the boy, who was then served a new drink after cabin crew were informed of the mix-up.

“We are in contact with a family after a mix-up of drinks occurred on a flight six months ago which resulted in a child having a few sips of an adult customer’s drink,” a Jetstar spokesperson told AAP.

“There was never any mention of the boy feeling unwell on the flight so we’re surprised by the claims now being made by Ms Pettigrove and her lawyers.” Shine Lawyers say no statement of claim has been filed at this stage and no court proceedings have commenced on the matter.