A quarter of English schools will get new funding to stay open an hour later every day - the extra time to be spent on activities such as sport and art.

The headmaster of a private Auckland school said a longer day has worked well for his pupils.

King's School headmaster Tony Sissons extended the hours to 7.50am to 3.40pm after he took over 12 years ago.

He told Leighton Smith studying music or a second language helps develop pathways in the brain.

"We found that the extra time allowed us to spend some time in those specialist subjects without compromising the maths, the literature and the social sciences".

Sissons said his students are getting international results academically, which is reinforcing the work the school's doing.

"The other thing was that through doing this programme, if a boy starts at the beginning of the school time, right through to year 8, he gets an extra year's tuition over and above any other school in the country".

A New Zealand educationalist is warning the move to lengthen school days could backfire.

Auckland University Associate Professor of Education Peter O'Connor said there's a recognition that for kids to do really well at school they need a broad, rich curriculum - and in England a lot of things have been squeezed out of the school day.

However, O'Connor told Mike Hosking there's little research to suggest longer school days in themselves make a difference.

"Japan for example and Finland, the two classic examples of high achieving education systems, actually have shorter days".

O'Connor said if the extra hours are being used for things that excite and engage kids, that has to be a positive.