She was taken to Ipswich Hospital with what are believed to be non-life-threatening injuries.
The armed man, who is believed to be in a relationship with the woman, has been holed up in the unit ever since. He has refused police demands to come out.
Police have had difficulty communicating with the man throughout the night.
“We’re extremely concerned about him because we understand that he did sustain injuries from a third party during the original disturbance,” Queensland Police Inspector Keith McDonald told 9 News.
“We’ve got two witnesses who were in the unit at the time who were threatened with a long-arm (gun).”
An emergency declaration was made at 12.52am. Elizabeth St is blocked off by police and negotiators are at the scene.
Anyone with information should phone Crime Stoppers anonymously on 1800 333 000