Wildrose Leader Danielle Smith says documents show the party accepted more than $102,000 between 2004 and 2010 from taxpayer-funded municipalities, post-secondary schools and school boards.
Smith says those are "prohibited corporations" under Alberta elections laws.
A senior official with the Alberta PC Association said the party will look at the information closely.
"Obviously my initial reaction is to take it very seriously. We're looking at the accusation and looking at the individual amounts and going back through our own records to see if there's something here," said PC Alberta executive director Kelly Charlebois.
"I don't have the answer yet but, as we have all along, we treat these accusations seriously."
The Wildrose has written to chief electoral officer Glen Resler and provided him with the documents that the party says detail 238 instances of improper donations from 41 different parties.
Individual donations ranged from $25 to $4,000 for such events as golf tournaments for members of the legislature, PC party annual meeting dinners and leader dinners for former premiers Ralph Klein and Ed Stelmach.
"That's over $100,000 of taxpayer dollars that should have gone to roads or classrooms or research that instead ended up in the PC party election war chest," Smith said at a Calgary news conference Thursday.
A report by the province's former chief electoral officer listed 45 cases of illegal contributions to the Tories between 2010 and 2011 from towns, municipalities, school boards and other publicly funded organizations.
The Tory government passed a law in 2012 prohibiting Elections Alberta from being able to disclose illegal donations received prior to 2010, so the Wildrose made access requests to municipalities, school boards and post-secondary institutions.
Smith said it doesn't matter that the illegal donations came well before Prentice was a member of the Alberta PC party.
"Mr. Prentice can't have it both ways. He can't take credit for all the things that the PCs liked and did like his schools announcement last week and then try to distance himself from all the things he didn't like," Smith said.
"He decided to run for the PC party and he has to run on their record and we have produced evidence that they have received $100,000 in illegal donations that have to be paid back."
The Wildrose party also recently released expense documents from new Health Minister Stephen Mandel's time as mayor of Edmonton.
The documents show Mandel charged taxpayers $225 to attend a Progressive Conservative party fundraiser in 2010. They also show that he accepted an improper $600 donation from the publicly funded Mazankowski Heart Institute in 2012.
Earlier this week, Mandel apologized and said he would pay the money back — if he is at fault.
Smith said Mandel's offer to repay the money is a good start and Premier Jim Prentice and the PCs should follow suit.
"We believe that the only way for them to demonstrate that this really is changed is to recognize wrongdoing occurred and the money should be paid back," Smith said.
"That's what Mr. Mandel did this week so I think that sets a good example."
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