Queensland Police have confirmed they fired lethal rounds during a siege in the Brisbane CBD last week.

Queen Street Mall was evacuated on Friday when Lee Matthew Hillier, 34, drew a handgun and threatened to harm himself.

The mall was locked down for more than an hour before police subdued Hillier.

Initial reports from police at the scene suggested only non-lethal rounds were used, but police have now confirmed lethal rounds were also used.

Hillier, from Caboolture north of Brisbane, is still in hospital with non-life-threatening injuries.

It is understood he was shot in the shoulder.

He has been charged with seven offences and is due to face the Brisbane Magistrates Court on Friday.

Queensland Police ethical standards command is investigating the response of officers during the siege.