There are continued calls for Premier Alison Redford to clear up questions about her role in handing a lucrative government contract to her ex-husband's law firm in Calgary.

Redford maintains the final decision on the contract was made by her successor as justice minister, after she left cabinet to run for the Progressive Conservative leadership.

However, documents obtained by the CBC show Redford signed off on the selection of a legal consortium, which includes her ex-husband's law firm.

On Friday, Liberal leader Raj Sherman called for an immediate independent inquiry into the allegations. 

"For years the PCs have been thumbing their noses at conflict of interest legislation, making patronage appointments and issuing crony contracts," said Sherman. "Now, public trust is at stake."

Yesterday, NDP Leader Brian Mason called on Redford to step aside while the matter is being investigated.

Tom Flanagan is a political science professor at the University of Calgary and managed the Wildrose Party's campaign in the last provincial election. 

He says it's unlikely the premier did anything legally wrong, but he adds the way the government is handling the story is hurting her politically.

"It probably was not a breach of the code as such in a legal sense but I think it was political bad judgment but now, as I say, now that they're in more of a cover-up phase," Flanagan said. "They're making things worse by constantly changing their story."

On Friday, Redford was in Calgary for a Diamond Jubilee ceremony.

Redford told CBC News she has been very clear with her involvement in the tobacco contract.

"I mean this is getting silly. This isn't what Albertans elected any member of the legislature to do and there's lots of issues that we need to talk about and those are exactly what we should be doing is getting down to the business of being MLAs and ministers and governing the province," Redford said.

"I must tell you that this was a person I was married to 21 years ago. I must tell you that when I see this person I don't think to myself and associate, 'Oh, this is my ex-husband.'"