A New Zealand mother who went on the run with her 7-year-old son to stop him undergoing radiotherapy says she will consent to the treatment if his cancer has returned.

A British High Court judge had been due to deliver a judgment next week on whether Neon Roberts should undergo radiation treatment following surgery six weeks ago to remove a brain tumour.

But his mother Sally Roberts, 37, has now said she would allow the treatment if a 1cm mass on Neon's brain, revealed in an MRI scan on Friday, was diagnosed as cancer.

"I don't think I will have a choice,'' she told The Times.


"I was so hopeful that we could just get on with other, less harmful treatments. But I will be backed into a corner."

Mrs Roberts, formerly of Auckland, has been locked in a court battle with her estranged husband, Londoner Ben Roberts, 34, over their son's treatment.

She had wanted to treat Neon with alternative medicines, fearing radiotherapy could cause him harm, including to his intelligence and fertility.

Mrs Roberts went on the run with the boy last week, sparking a nationwide search until they were found by police five days later.

At a hearing over the weekend, High Court Justice Sir David Bodey delayed his decision on Neon's treatment until December 18 due to "medical developments".

Neon had been due to have another MRI scan and a spinal fluid test in hospital overnight (NZT).

Even if the scan is clear, which Mrs Roberts is confident it will be, the court could order Neon to undergo radiotherapy.

Doctors at a previous hearing said he needed the treatment soon to survive.