Third teen charged after NSW officer hurt

A third teenager has been charged following an attack on a NSW Police officer who was kicked in the face while trying to make an arrest.

The 37-year-old father of two was one of three officers injured during the confrontation Marsfield on Monday night.

He suffered serious head injuries after falling to the road and remains in Royal North Shore Hospital.

It's alleged police were responding to a call for help from security guards at the Macquarie Shopping Centre when they came across the teenager.

The 16-year-old boy was on Tuesday charged over both assaults, while another teen, 17, was charged over the shopping centre incident.

On Thursday, a third teenager was charged with robbery in company and affray after police raided his Epping home.

The 18-year-old was granted conditional bail to appear at Burwood Local Court on July 31.

The injured officer is expected to face a long road to recovery.

"He's a lovely young officer ... our thoughts and best wishes are with him and his speedy recovery," Detective Superintendent John Duncan said on Tuesday.

Police say investigations into the alleged assaults are continuing.