A judge has decided on where a 5-year-old girl goes to school after a separated couple's stand-off ended up in court.

The judge, in an urgently heard case, has sided with the father who had argued that the girl should attend the same primary school as his other children, her sisters who she has a close bond with.

The girl's mother wanted her to attend her local, in-zone school.

Just days before the child was due to start her primary education, a High Court judge had to make the ruling for the parents who separated two years ago and have a joint care arrangement.

It came after a Family Court ruling initially agreed with the girl's mother and had her going to the local school.

The Family Court judge, who found both parties were doing a good parenting job, said, generally, that attending a school within their neighbourhood, and within their school zone, allows the child to interact and form friendships with other children in the area.

Friendships formed at school and within a child's community are important to a child's development and hard to replicate out of zone, the judge said.

He also observed that preschool friends would be going to the school close to the mother's home.

The judge said he had to balance the advantages of the girl attending the same school as her sisters against the impact on her not being in a position to form friendships with children attending her local school and living within her community.

He also noted that the father couldn't collect his daughter from his school of choice until after work around 5.45pm but would organise afterschool care.

The judge found the father's approach to be based around his needs and wishes and that he was overlooking that the decision must be about his daughter's best interests and welfare.

The Family Court decision also changed a long-standing 2:2:3 shared care regime, where the girl was said to be "settled and flourishing", to a new two-week cycle where the
father would see her much less.

The father rejected the claims and made an urgent appeal to the High Court, pleading for the girl to attend the same school as her sisters.

At the High Court hearing earlier this month, the father said everything he does is for his children.

"They are my life. I organised my working life around them. I am a working professional and so that means I do have less flexibility. But I do not believe being a working parent should be held against me — I am trying my best to support my daughters, to be a part of their lives as much as possible," he said.

And in a newly-released decision, the High Court concluded that the Family Court judge did not properly apply the principles in the Care of Children Act 2004 when ascertaining what care arrangement and attendance at what school would "best promote the welfare and best interests" of the child.

The benefits of attending the father's choice of school, and being alongside her sisters, outweighed other considerations, the High Court judge ruled.

And while she accepted that friendships formed at school are important to a child's development, the judge was not persuaded by the Family Court judge's suggestion that friendships are unlikely to be maintainable out of school hours due to distance.

"There are so many factors that may influence how relationships are developed and maintained that I find this to be conjecture rather than a matter of fact," the High Court judge said.

The judge directed that the child attend the same school as her sisters and that the 2:2:3 care arrangement in place prior to the Family Court decision be reinstated.