Four oversubscribed primary schools will hold a ballot for places tomorrow.
It will be the first time since 1995 that this has been seen at the early 2A2 registration phase, which caters for children whose parents or siblings are former pupils of the school.
This year, a new rule has put the squeeze on Phase 2A2. It requires schools to reserve at least 40 places which are divided equally between children applying in Phase 2B and 2C.
When registration for this phase closed yesterday, CHIJ St Nicholas Girls' School in Ang Mo Kio had 24 children vying for 14 spots, while Henry Park Primary in Bukit Timah had 59 children applying for 46 vacancies.
At Radin Mas Primary in Bukit Merah, 67 children applied for 60 places, and Nan Hua Primary in Clementi had 55 children competing for 42 spots.
All four will conduct a ballot for children staying outside a 2km radius of these schools.
At Yu Neng Primary in Bedok, a total of 62 children applied for 59 places, but the school will not conduct a ballot as it will give preference to all Singapore citizens who applied because it has space to cater for them.
The primary school registration exercise started this month and has seven phases. Phase 2A2 is the third of these.
Next up is Phase 2B, which will be held next Monday and Tuesday, and is traditionally when the balloting frenzy begins. This phase is for children whose parents are school volunteers or grassroots leaders, or have church or clan links.
There is also balloting in Phase 2C - the most competitive phase - which is for children with no connections to schools.
In the past, some of the more sought-after schools have had as few as 20 places combined in both these phases.
The last school to hold a ballot at Phase 2A2 was Anglo-Chinese School (Barker Road) 19 years ago.
However, this year's early rush for places is not as big a headache for parents as it sounds.
It will mean that those registering in the later phases will have at least 40 guaranteed spots up for grabs in their choice schools.
Madam Jennyfer Aw's six-year-old daughter faces a ballot at Henry Park Primary - the alma mater of both her parents.
"My daughter is the oldest of three children. I have two younger boys, who are four years old and six months old, so it's crucial which school she gets into," said Madam Aw, 32, a housewife.
"By the time we heard about the new rule, it was too late to join the alumni association."
If her daughter misses out on a place at Henry Park, Madam Aw said she plans to enrol her in one of the schools near her Punggol flat - Horizon Primary, Edgefield Primary or Punggol View Primary.
Meanwhile, parents at other schools were relieved to have secured places for their children.
Mr Tan Boon Gim, 41, who registered his six-year-old son Gregory at Catholic High School in Bishan, is relieved not to face a ballot. The school has 24 children registering for 28 places.
"When the new rule was announced last year, my wife and I realised that those registering in Phase 2A2 might be squeezed out," said Mr Tan, who runs a property website and has another two-year-old daughter.
"We then moved house so we could be nearer to Catholic High."
Within three months of the announcement of the rule, the family moved from their house in Newton to an apartment in Sin Ming - within 2km of Catholic High.
Ms Yasmin Lazaroo's six-year-old son was given a spot at St Stephen's School in Siglap, which his father attended.
But Ms Lazaroo, 31, said she may try for a place at St Andrew's Junior School in Phase 2B.
The senior marketing and branding executive said: "It's less than 1km from my mum's place in Potong Pasir, and she looks after my son when we are at work."