At least six primary schools here have adopted a no-frills birthday celebrations.

No goody bags, no sweet treats and no gifts. Instead, a simple birthday song sung in class should suffice.

Some primary schools are laying down the law on birthday festivities in schools, saying they should be kept to "no-frills" celebrations.

This, they say, will curb concerns about food allergies and the consumption of junk food.

Just as important, it prevents students from making comparisons between the haves and have-nots.

The Straits Times found that at least six schools have issued such guidelines in recent years: Dazhong Primary School, Pei Chun Public School, Geylang Methodist School (Primary), Oasis Primary School, Springdale Primary School and Riverside Primary School.

The Ministry of Education has no policy on this, allowing individual schools to decide.

But some parents whose children are in these schools are unhappy, saying that they celebrated their children's birthdays in pre-school and should be allowed to continue the custom in primary school.

Housewife Betha Bhanu Valli Kalyani, 36, who has a son in Primary 2 in Springdale Primary, used to mark birthdays with him in pre-school by distributing goody bags containing toys and tidbits to his classmates, in addition to ordering balloons and a cake.

"He used to have celebrations in kindergarten, so I don't see why he is not allowed to do so now," she said.

Housewife Geraldine Tan, 41, who has a son in Primary 2 at Holy Innocents' Primary School, said his school does not discourage such celebrations.

Making comparisons "is part and parcel of life and shielding children from that is a little excessive", said Ms Tan.

But the schools say that they have their reasons.

In a circular sent in January, Oasis Primary in Punggol told parents not to organise birthday celebrations within the school.

As these celebrations "invariably involve food", there were concerns that this may trigger food allergies, principal Ong-Chew Lu See wrote in the circular.

"There is also a concern that the students will start to compare between the haves and have-nots," she added.

"While we want our students to build quality relationships within the class, we do not want to encourage comparison among them."

That same month, Springdale Primary in Sengkang also told parents to avoid giving birthday goody bags or gifts to other pupils in school, after receiving feedback from parents.

Such guidelines have been in place at Riverside Primary in Woodlands since it opened in 2013. Instead of celebrating through cakes, gift packs or other items which are brought to school, pupils' birthdays will be marked through "simple and meaningful" practices like singing a birthday song in class, the school said.

Riverside Primary's principal, Mrs Sharon Siew, said parents have largely approved of simple birthday celebrations, which promote a healthy lifestyle by reducing the junk food that pupils consume and cultivates a "culture of simplicity and appreciation".

"Some parents show their love by wanting to celebrate their birthdays in a bigger way, but others love their children in simpler ways...

"Parents have said that this avoids comparison (of material wealth) among pupils," she told The Straits Times.

Civil servant Nur Azlina, 36, who has a Primary 2 daughter and Primary 1 son in Riverside Primary, likes the school's "no-frills" stance.

She recounted how her son's classmate had given out customised pencil cases inscribed with the name of each child during a birthday party in kindergarten and he had asked her if they could do something similar for his birthday.

"Children already start making comparisons at a young age and it makes things difficult for parents who come from different family backgrounds," said Madam Azlina.