A 24-year-old man armed with a knife has been shot dead by police at Ipswich train station, west of Brisbane, following a stand-off with officers.

The incident occurred on one of the station’s platform about 4:15pm on Sunday.

Train services remain suspended in Ipswich and buses are replacing the Ipswich and Rosewood train lines between Thomas Street and Bundamba stations.

Ipswich Acting Superintendent Mel Adams said three officers attended the call at the Ipswich train station.

"Upon attending the station they were confronted by a male person. During that confrontation, which was very brief, the male person was shot by police and unfortunately that male person is deceased," Ms Adams said.

"The incident took place on the train station platform there were a number of witnesses."

She said the officers were shaken up after the incident.

"We are offering all the support we can to our Police Officers, it's obviously a traumatic time for them," she said.

Queensland Police Union (QPU) president Ian Leavers said the officers involved would cooperate fully with an investigation by the Ethical Standards Command.

"In incidents that are like this where shots are fired, it takes a tremendous toll on police and sometimes they never get over it," Mr Leavers said.

"I've spoken to the police involved and as you would expect they are quite shaken.

"They were simply doing their job.

"If we have to we will use force, but we look at all options and using a firearm is the last resort for police.

"We are very thankful that they are safe and well."

Police are appealing for anyone who was on the platform at the time and has not yet spoken to police to contact them.