Another business organisation is urging Birmingham City Council to "get off the fence" and back a move to build Britain's first super-casino at the National Exhibition Centre.
The Institute of Directors in the West Midlands said Birmingham should join with Solihull Council in submitting a joint bid to the Government's Casino Advisory Panel.
The IoD is following in the footsteps of Birmingham Forward, the professional services lobby group, which is also backing the NEC, while Birmingham Chamber of Commerce and Industry has recommended its members to support the NEC casino option.
Pressure from the business community, if accepted by the city council, would put paid to a rival proposal by Birmingham City Football Club for a £340 million stadium sports village and casino at Saltley.
IoD regional chairman John James said Birmingham City Council risked being left too far behind the competition to catch up.
Mr James said: "Coventry's ambitious plans for the Ricoh Arena have been in place for over 12 months as have nearly all the local authorities with rival bids in the rest of the country.
"Birmingham simply cannot postpone making its mind up any longer.
"Just don't let the legacy of Birmingham's contribution to the super-casino debate be the words 'our indecision was final'."
Mr James said the Birmingham City FC submission was well thought through and had clear regeneration benefits, but the NEC case was much stronger in terms of its acceptability to the community, transport infrastructure, and the economic benefits for the West Midlands as a whole.
"The income stream to Birmingham from the NEC super-casino will be significant and there is nothing to prevent Birmingham Council ring-fencing all or part of the annual income and committing these monies to specific projects including a new city sports stadium - indeed they should be encouraged to do so," Mr James added.
Birmingham City FC managing director Karren Brady said the views of the business organisations took no account of public opinion, which was solidly behind the football club's proposal.
Ms Brady added: "Regeneration is the only thing that matters and the Birmingham sports village wins hands down."