An alleged gunman has been shot dead by police after a six hour standoff on Monday night. 

Peter Pilkington is accused of storming a NDIS service provider on Compton Road in the Brisbane suburb of Stretton, where five people were forced to barricade themselves from the gunmen. No others were injured.

Police Commissioner, Katarina Carroll, said there is an internal investigation underway through Queensland's Crime and Corruption Commission and that The Ethical Standards Command would also investigate the incident.

Less than 24 hours after Mr Pilkington's fatal shooting, another man was injured with non-life threatening injuries when officers opened fire at a property south-west of Brisbane in the Logan suburb of Flagstone, after reports he was making threats to harm people he knew. Investigations are ongoing.