Officer stabbed by alleged sex offender in 'serious' condition

A senior NSW Police officer has undergone surgery and is in a serious but stable condition after being stabbed by an accused child sex offender.

A senior NSW Police officer is in a serious but stable condition after he was stabbed by an accused child sex offender during an arrest in Sydney's southeast.

The 45-year-old, named in reports as Detective Sergeant John Breda, was stabbed in the chest and abdomen in the beer garden of the busy Maroubra Junction 

Hotel on Australia Day afternoon.

He attended the hotel with colleagues to arrest 33-year-old Nick Newman, who was the subject of an arrest warrant in relation to alleged child sex offences.

Police said the officer was stabbed during a "confrontation" and Newman was shot dead by two other officers.

Det Sgt Breda was taken to St Vincent's Hospital in a critical condition.

He underwent surgery and on Saturday he remained in the intensive care unit in a serious but stable condition, a police spokeswoman told AAP.

Assistant Commissioner Mark Walton said the two other officers were traumatised about how the "relatively routine situation" escalated.

A critical investigation has been launched which will be subject to an independent review.

The day before the stabbing, police issued a public appeal for information on Newman's whereabouts.

He was scheduled to appear in Penrith Local Court on Wednesday but failed to appear.