POLICE are trying to find a home invader who was badly hurt when he tried to force his way past an 83-year-old black belt home owner last night.

The home invader, a muscular man in his thirties who may be linked to other burglaries, broke into the high-set home in Gilruth Rd, Kenmore at about 8.30pm.

Inside were Edwin Dowdy, 83, and his wife Jutta, 76, who have lived in the property in the quiet Kenmore street since 1966.

When the couple - who both have black belts in the Japanese art of Aikido - realised there was an intruder in the house Mr Dowdy grabbed a knife from the lounge room he had kept for security and went to confront the burglar and warn him he was armed.

He said he confronted the intruder and told him he had a knife, but the man tried to push past him and ran on to the blade.

The injured burglar - who was bleeding heavily from a knife wound to his stomach - took two of Mrs Dowdy's handbags and ran on to the balcony and jumped to the ground.

A large amount of blood was visible there this morning.

He then fled down with the Dowdys in pursuit and tried to steal a car from a few doors down.

The vehicle, which belonged to a P-Plater, had blood on it this morning and there was a lengthy blood trail on the street.

When the thief was unable to break into the car he fled on foot and police today issued a plea for public help to locate him, advising that the amount of blood at the scene "indicates that the man needs urgent medical attention".

They say he is likely to have a "noticeable injury to his lower front or side torso".

Police have warned homeowners that while they have a right to defend themselves from intruders only "reasonable" force should be used.

"Our advice is that people should avoid confronting anybody it's not my advice that people should arm themselves and confront anyone in a house," Detective Inspector for Brisbane West Robert Hitch said.

"People have a right to take action to defend their own person, to defend their dwelling and to defend other people. The force that they use must be reasonable and must fit the circumstances, it must be considered in relation to the threat that they're facing," Det Insp Hitch said.

Det Insp Hitch said police were unsure how seriously injured the intruder may be and said they are investigating how he was hurt.

Blood was found inside the house and a trail of blood was found in streets around the home.

"The owner of the home has been interviewed....the reality is we don't know what injuries have been caused, we don't know who the injuries have been caused to. We have insufficient evidence in relation to what sort of actions have taken place in the house," Det Insp Hitch said.

"We're appealing for anyone who may have information in relation to who the intruder is (to come forward)," he said.

Det Insp Hitch said police were investigating if last night's break and enter was linked to other recent burglaries in Kenmore.