Johns, 44, collapsed in a coffee shop at Yamba while on holiday on the NSW North Coast, the paper reports.

The former Newcastle Knights, NSW and Kangaroos star says he's on medication to treat his condition, which has involved a spate of seizures over the years.

"I've got some medical stuff going on," Johns told the paper on Sunday.

"They're seizures that have been going on a while.

"I'm seeing the right doctors and they are doing all the tests and have got me on medication."

His younger brother Matthew, a Fox Sports presenter and former Newcastle star, said his sibling could feel his seizure coming before it hit him.

"Next thing he can remember is waking up on the floor," Matthew said.

"He's had a few seizures in the last couple of years but his last one was probably 12 months ago.

"He seems to think it comes on at times when he's really tired."

The older Johns went public about his battle with bipolar disease in 2007.

Australian Associated Press