Police investigate Taser failure after man shot dead by officer in Sydney

Police are investigating why a Taser failed to work when it was deployed before a man was shot dead by an officer in inner Sydney overnight.

Officers went to a block of units on Franklyn Street in Glebe with concerns for a man's welfare about 11.50pm.

When they arrived, a 43-year-old man allegedly confronted them with a knife.

READ MORE: Auckland construction site gunman was under house arrest

"He certainly moved towards police with what I was advised was a large carving knife," Assistant Commissioner Anthony Cooke said.

"Very clearly, he was suffering injuries to himself."

One officer fired a Taser and another their gun.

The man was treated by paramedics but died at the scene.

"I am not quite sure why the (Taser) attachment was not effective in those circumstances but we are talking about quite a confined space here and unfortunately in these circumstances on this occasion the Taser was ineffective," Cooke said.

"These things … occurred in seconds in a very confined space in circumstances where a person was armed with a knife in very, very close proximity to police. 

"So in these circumstances, it is very difficult to judge."

The man was well known to police for a range of circumstances.

Police have spoken with his family, who were very upset.

An investigation is now underway into the circumstances surrounding his death.

Sign up here to receive our daily newsletters and breaking news alerts, sent straight to your inbox.