Man stabbed in chest at Newcastle park

A man stabbed in the chest after intervening in an argument at a seedy Newcastle park knew his attacker, police suspect.

It's believed a small group of people were at a King Street park at lunchtime on Wednesday when a dispute broke out between a man and woman.

When another man in the group stepped in, police believe, a third man from the same group stabbed him in the chest.

Newcastle City Inspector Trevor Shiels scotched suggestions a love triangle sparked the bloody altercation.

"Investigations are under way, but certainly no indication of that at this stage," he told AAP.

But he added the area was well known to local officers.

"In the past there have been drug-related issues and we conduct high-profile operations in that area," he said.

The 43-year-old stabbing victim is in John Hunter Hospital in a stable condition, according to a spokeswoman.