A business park on a former tinplate works remains vacant, despite £11m being spent on the project.
Plaid Cymru AM Dai Lloyd said Swansea residents were frustrated by the lack of progress at Parc Felindre.
Conservative AM Suzy Davies said there needed to be reassurance that the investment is recoverable.
Responding in the assembly, Finance Secretary Mark Drakeford said officials have been trying to attract people into the site.
In 2010, it was announced that European and Welsh Government cash would be spent at the site.
The work includes a new internal road and providing electricity, gas, water, drainage, lighting and high-speed broadband access.
There were doubts at the time whether the site would find tenants.
Speaking in the Senedd, Dai Lloyd, AM for South Wales West, said: "Since the bringing down of the steel works in that area, we have seen many plans to bring business to that local park, but its still vacant.
"There's local frustration about developments in this park which has the potential to create hundreds of jobs."
"I think we need some reassurance that the investment is recoverable."
Mr Drakeford said he was sure Economy Secretary Ken Skates would want to "make sure there is a proper return to the public on the investment that has been made to the site".
He said: "We have been trying to attract people into help us develop the site."
He added: "We have been encouraged by the standard of developers and occupiers who have now expressed and interest in the site and my colleague Ken Skate is anxious to move ahead so we overcome the difficulties that Dr Lloyd has identified."