SAN FRANCISCO - Public schools can use race as a consideration to help balance the composition of public high schools, a US appeals court ruled on Thursday.

In a 7-4 decision, an 11-judge panel of the US 9th Circuit Court of Appeals overturned a 2004 three-judge panel ruling on the controversial and long-debated issue.

The judges were considering whether race is a permissible factor in deciding which students will be admitted to oversubscribed high schools in Seattle, Washington.

The Thursday ruling swung back in favour of the lower court's earlier decision.

"It is true that for some students their first choice of school, based on geographical proximity, will be denied because other students' choices are granted in order to advance the overall interest in maintaining racially diverse school enrollments," a judge wrote for the majority.

But "the district's compelling interest is to avoid the harms of racial isolation for all students in the Seattle school district". Four out of the 11 judges dissented.

"The district's use of the racial tiebreaker to achieve racial balance in its high schools infringes upon each student's right to equal protection and tramples upon the unique and valuable nature of each individual," Judge Carlos Bea wrote for the dissenters.

"Even if well-intentioned, the district's use of racial classifications in such a stark and compulsory fashion risks perpetuating the same racial divisions which have plagued this country since its founding."