Radio broadcaster Alan Jones will be off air indefinitely as he seeks treatment for severe back pain in hospital.

The Sydney-based shock jock missed his regular 2GB and 4BC breakfast show on Monday and again on Tuesday.

"He's currently in hospital being treated for severe back pain," his fill-in Chris Smith said.

"His doctors are working to establish exactly what the problem is. The end result is he'll be back as soon as he can but we're not sure exactly when that will be."

AAP

Jones had surgery on his back in November 2016 and several subsequent neck operations, forcing him off air for four months.

Jones was recently reportedly disciplined by his 2GB bosses following a recent spate of incidents, including the costly Wagner defamation case and his use of the racist phrase “nigger in the woodpile” on air.

The reference was in relation to the ongoing Liberal leadership chaos, in the lead unto Prime Minister Malcolm Turnbull's rolling.

Jones also apologised last month, saying he regretted his comments directed at the Opera House’s chief executive Louise Herron.

The broadcaster initially called for her sacking over opposition to displaying advertisements for the Everest horse race on the sails of the opera house.