TORONTO -- Ontario's opposition parties are demanding the release of expert reports into the $106 million Nipigon River Bridge, which failed last January less than two months after it opened.

The steel decking on the bridge lifted about 60 centimetres, causing a 24-hour closure of the east-west link on the Trans Canada highway and forcing about 1,300 trucks a day to detour for several weeks.

Progressive Conservative transport critic Michael Harris said Friday that two independent labs tested the bolts on the bridge and submitted reports to the government, and he believes there's also an internal Ministry of Transportation report into the failure.

Harris added that Transport Minister Steven Del Duca is sitting on the reports in hopes of finding someone else to blame for the sudden failure of the first cable-stayed bridge ever built in Ontario.

"That internal analysis that's been done by the MTO will likely show exactly where the finger can be pointed, and that finger may be turned back at them," he said. "I think it's more about protecting their own hides than making sure the public has all the information."

Del Duca issued a statement Friday saying it would be reckless to release "limited information in piecemeal fashion prior to having all of the facts," and promised to release all the reports into the bridge failure sometime this fall.

"Any assertion that the Ministry of Transportation is hiding information is false and represents an unfortunate attempt by the opposition parties to politicize a process that is being led by engineers and other appropriate experts and research bodies," he said.

New Democrat transport critic Wayne Gates said people deserve to know what is in the reports, and what is being done to fix the problem so it doesn't happen again.

"The ministry has two reports on what went wrong," said Gates. "Ontarians shouldn't have to wait until next fall to learn why the Nipigon bridge failed."

Del Duca said government bridge engineers are conducting their own analysis, as is an independent engineering consultant with expertise in cable-stayed bridges. Their findings will be compared, and only then will the results -- including the already-completed bolt analyses -- be made public.

"When the entire investigation is completed, which we expect will be in the fall, the reports, expert findings and details from the engineers will be made public," he said.

"This is the prudent approach, not the political one, and it will provide all Ontarians with the information they expect and deserve regarding this incident."

Harris said the minister obviously wants to chose the timing of the release of the reports so it's to the government's advantage.

One lane of the bridge was re-opened to light vehicles one day after the failure when engineers placed huge concrete blocks to lower the deck to road level, but it was nearly a month and a half before a second lane was open to traffic.

The government said the temporary repair still functions as expected, and "the bridge remains safe for use by all."