Councillor Jim McCabe said he would be "bitterly disappointed" if the Scottish government reneges on £70m of funding promised by Scottish Enterprise.
He said the money would ensure progress on the rest of the 450 hectare site.
The £31m regional sports facility will be a key venue for the International Children's Games held in Lanarkshire in 2011 and will be used by athletes training for the 2012 Olympics and the 2014 Commonwealth Games.
Construction work began in January and the centre is expected to open to the public in Autumn 2010.
Funding has come from North Lanarkshire Council, Ravenscraig Ltd and the government agency, sportscotland.
Council Leader, Mr McCabe, hailed the progress being made on the facility but said more money was now needed to kick-start the planned £1.2bn generation of the rest of the former steelworks site.
-- Advertisement --
He said: "On a site renowned for steel making, it is very satisfying to watch the structure starting to take shape.
"Along with the recent opening of the new Motherwell College campus, this project demonstrates the commitment of all those involved to realising the vision of a new thriving community at Ravenscraig.
"However although the sports facility is on track and on budget, the Ravenscraig project as a whole is not."
He added: "There was £70m supposed to come from Scottish Enterprise to allow us to put the infrastructure in place for a new town centre.
"Scottish Enterprise has been reduced and the Scottish government fall heir to that commitment.
"Without that £70m we go nowhere."
A spokesman for the Scottish government told the BBC that it was working closely with North Lanarkshire Council to help facilitate further development on the Ravenscraig site.
He added: "We are pleased to see the excellent facilities now in use, and being completed, on the former steelworks site, including a college and regional sports facility, and have helped prepare the site for further development, with over £20m delivered through Scottish Enterprise, which remains involved in the Ravenscraig Ltd joint venture.
"We are in discussions with key partners, including the council and Scottish Enterprise, about the importance of realising the site's potential and attracting private sector interest and investment."
The regional sports facility will include a full size 3G indoor and outdoor football pitches, an athletics track, dance studios and sports hall.
It will be used as a training facility for elite athletes and as a community hub for those participating in sports at grass roots level.
The building design incorporates a serrated roof which allows natural light to enter the facility all year round.
The huge indoor football hall will be also be used for music events and functions, with a capacity of 5,000.
(BMcC/KMcA)
