"If you see these offenders do not approach them and phone police immediately on 111."
Detective Inspector Darryl Sweeney said a team of officers is now working through evidence and whether both crimes are linked.
"Firstly, and important, we have provided support to the staff and ongoing victim support, understanding that they did face a traumatic situation.
"At both the Embankment Hotel and O'Shea's, staff and patrols did the right thing and obeyed the instructions of the offenders."
Police officers will also be visiting hotels around Christchurch to provide advice and reassurance.
Anyone who recognises any of the people in these photographs, or suspects they know those involved, is asked to contact Christchurch Police on 03 363 7400 or Crimestoppers on 0800 555 111.