A decision on whether to back the £425m Circuit of Wales with public money will not be taken until after local elections in May.
Economy Secretary Ken Skates said the company that wants to build the motor racing track near Ebbw Vale still had not provided all the information required by the Welsh Government.
Mr Skates said previously he would look at the latest financial plans.
Developers want ministers to guarantee half the cost of the project.
Mr Skates told AMs that the developers did not provide the paperwork needed to start the due diligence until late last week, adding: "It's also regrettable that the information is currently incomplete."
He said he hoped to report back to the cabinet by mid-May - after the council elections on May 4.
The track would be built with private funding and would host Moto GP races.
Mr Skates told the Senedd on Wednesday claims that the track could create up to 6,000 jobs in one of Wales' most deprived communities will be "thoroughly scrutinised" by consultants who are carrying out the due diligence on behalf of the Welsh Government.
A "fit-and-proper persons" test started this week into directors of the Heads of the Valleys Development Company, the company behind the scheme.
"We will not by-pass due diligence for any decision," Mr Skates said.
"We have been applying immense pressure to the developers to provide the information that is required of them by the consultants. With that information due diligence can be completed."
Image copyright Circuit of Wales
It was in the company's interest to comply "so the people of Ebbw Vale and the valleys know whether this is a viable project", he added.
Responding to the delay, Plaid Cymru economy spokesman Adam Price said: "If there has been a problem with a lack of complete information why hasn't the government done what the private sector would do in these kinds of situations, in projects which are far larger than this, which is to get everyone in a room ... so that we can actually sort this out?"
Auditor General Huw Vaughan Thomas is separately investigating more than £9m that the Welsh Government has already provided to the scheme.
His report is expected some time in April.