An allergy scare involving a three-year-old toddler has prompted Singapore Airlines to review the serving of nuts on board its flights.

Marcus Daley suffers from anaphylaxis, a potentially life-threatening condition which can be triggered by food including peanuts and shellfish.

He was travelling with his parents to Melbourne after a holiday in Thailand.

He suffered a severe allergic reaction after other passengers around him opened their snack packets of peanuts.

His father Chris Daley, a doctor specialising in respiratory issues, told the Australian Broadcast Corporation that his son received a special nut-free meal but quickly became severely ill when others were eating their nuts.

"He started vomiting, his eyes were starting to swell and he couldn't speak properly," Mr Daley said, adding that the family was less than an hour into their seven-hour flight home.

Thankfully, the Daleys had brought anti-allergy medication, which quickly brought the situation under control.

'A nut-free cabin'

Major airlines such as Qantas, Air New Zealand and British Airways do not serve nuts during its flights or offer them in in-flight meals.

Singapore Airlines issued a statement on Wednesday saying it would review the serving of nuts on board all flights.

"As soon as our crew were made aware of the situation, they immediately removed all packets of peanuts from the area around the affected passenger and his family," the airline said.

"Our crew suspended the service of peanuts in the Economy class cabin for the remainder of the flight."

It added that passengers with nut allergies were able to request nut-free meals when making their flight bookings but said that they were not able to guarantee "a nut free cabin".

"We do not have any control over passengers consuming their own snacks or meals on board, which may contain nuts or their derivatives," the airline said in reply to a customer's comment on its Facebook page.

The incident has resulted in heated debate on social media, with many criticising the family's "irresponsible behaviour".

"They know the severity of their son's allergy and should have simply ensured he took the meds prior to the snacks being served," wrote Facebook user Melissa Chua, who described herself as a "frequent traveller".

"Nuts are one of the most common snacks served onboard. There are many people with nut allergies out there but you don't see them making such a fuss.

"Their sense of entitlement is so strong, to suggest an airline not serve nuts simply due to one passenger.

"When their son grows up, he'll have to learn that the world doesn't revolve around him."

Ali Fadli Mohd wrote: "Shouldn't their child have been given a mask to wear since he is so allergic? What if somebody brought peanuts along in their bag and opened it in the airplane?"

The online anger was overwhelming but some commented in support of the Daleys.

Yvonne Chua Kaiyin criticised "the lack of understanding" about such allergies.

"Because it occurs in an enclosed place, the boy can't escape it. His parents did bring his medication so they did prepare and they are responsible. Some people just don't understand."

Liz Ong, a mother of one, shared on Facebook: "My child has a life threatening food allergy. I am glad that this little boy survived the flight and I am so disappointed seeing these comments. We are responsible parents but no amount of medication can prevent an allergy in an enclosed space full of peanut dust circulating in the air during a flight.

"It may be a small inconvenience for you but I hope people will reconsider their decisions, to help keep a child safe."