A couple has been charged with manslaughter and police are searching for another woman after a security guard was allegedly fatally assaulted while trying to stop an attempted break-in at an inner-city Sydney shopping centre.

Witnesses told police a 28-year-old Maroubra woman, a 33-year-old Randwick man and another woman allegedly punched and kicked the security guard, 68-year-old Hans Schulz, after he interrupted them during an alleged break-in at the Wendy's ice-cream kiosk in Broadway Shopping Centre last night.

Police said the group, who were with two children aged three and five, then fled the centre. They identified the woman for whom they are searching as Raelene from nearby Surry Hills.

When emergency services arrived about 8.10pm (10.10pm NZT), they found the guard with serious injuries on the shopping centre's ground level. He was taken to hospital, where he died a short time later.

The couple were arrested at a   bus stop near the shopping centre shortly after and charged overnight, police said. The two young children were with the couple at the time of the arrest, police said.

''It's hard to say at this stage as to what their intentions were but they had certainly gained access to one of the shops after trading hours,'' Detective Inspector Paul Pisanos said yesterday.

Police sealed off the area, photographing and taking fingerprints at the Wendy's ice-cream kiosk in the middle of the ground floor.

Pisanos said relatives of the pair would be called to look after the children. ''The kids were with them, they're young. They were young kids,'' he said.

The couple were refused bail to appear in Newtown Local Court today.

A report would be prepared for the Coroner.

- Sydney Morning Herald