Retired Newcastle halfback Andrew Johns says he refused the option of surgery that could have saved his football career.

Johns retired from the NRL after neck scans revealed he had a bulging disc that was within one centimetre of his spinal chord, bringing to an end one of the most illustrious rugby league careers.

The former NSW and Australian Test captain said Professor John Yeo and Knights club doctor Neil Halpin discussed whether surgery to fuse the protruding discs would enable Johns to resume playing again.

But Johns, 32, refused to consider the surgery and told doctors he would retire from the game immediately.

"There was talk if they fused the discs you could possibly play on (but that was) if I was 22, not 32," Johns told the Nine Network.

"But that makes the area above and below the fusion a lot more susceptible to injury.

"I decided to hang them up, I said before you go any further I'm going to retire so at least I could say I retired without a doctor telling me I had to finish up."

Johns said it was likely he will require surgery on his neck in the future and he would have a cortisone injection in the next couple of weeks so he could resume his much loved past time of surfing.

"The professor said maybe in time I might have to have surgery in 10 or so years," he said.

"In the next few weeks I will have a cortisone injection to hopefully settle it down and that will enable me to go surfing and stuff but in no case can I partake in any body contact ... (not even) playing touch football so it's pretty serious."

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