Police were last night working to determine whether the two incidents were linked.
The first incident unfolded when two heavily disguised offenders entered the St Kilda Tavern in Prince Albert Rd just before 11.30am.
The intruders presented a firearm to bar staff and demanded money, a police spokesman said. After not being able to obtain any, they ran off into Young St.
Later in the day, marked and mufti police cars were parked near the St Kilda Tavern and officers were seen coming and going from the business.
Officers could also be seen investigating side streets and photographing the outside of the pub.
A staff member working at the tavern on Sunday afternoon declined to comment.
Cash was taken from the premises, a police spokeswoman said.
Two marked and two unmarked police cars attended the incident, and police were canvassing the area, asking businesses nearby whether they had CCTV footage available.
Last night a police spokeswoman said despite there being two offenders entering the St Kilda Tavern and only one entering the TAB, police remained "open-minded in regards to the two offences being linked".
"Information is currently being reviewed and inquiries will continue into both matters to identify those responsible.
• Police 105; Crime Stoppers 0800555-111.
