Redford, who once worked with Mandela before she entered politics, was invited to travel with Prime Minister Stephen Harper as part of a Canadian delegation attending the former South African leader's funeral in December. The premier's office confirmed she travelled with an assistant.
"I'm not challenging the number. I'm surprised by the number," she said Wednesday after making an education announcement south of Calgary. "I don't think it was acceptable. I was disappointed. You can appreciate that it was a very fluid week and you can appreciate I'm not making my own travel arrangements in those circumstances."
Redford took a provincial government plane to Ottawa to catch the free flight with Harper to South Africa, but she flew home early on a commercial flight at a cost of $10,000 to attend the swearing-in of her new cabinet.
"I have to say that if, at that point of time, we had understood ... what some of those actual costs were going to turn out to be, and also how fluid the prime minister's schedule was, I think I would have chosen not to go," Redford said.
Opposition leaders have noted that Nova Scotia Premier Stephen McNeil billed taxpayers less than $1,000 to go to the funeral.
They say Redford's lavish spending on travel abroad shows contempt for taxpayers.
Wildrose critic Rob Anderson said Wednesday that Redford ought to have known the cost of her trip, or at least could've taken a good guess.
"One might ask how the premier didn't know taking a private jet to Ottawa wouldn't be expensive," said Anderson, who added that Redford needs to pay the money back.
He said the trip, along with Redford's recent $120,000 journey to India and Switzerland, suggests she has delusions of royalty.
"She obviously thinks she's the Queen of England. There's some kind of an identity crisis going on here. She's not. She's the premier of Alberta," he said. "She needs to start showing respect for the taxpayers that she represents and spends the money from."
Redford has also been criticized since the release of her government's list of public-sector employees who make more than $100,000 a year,
Redford's chief of staff, Farouk Adatia, led the way on the political side, pulling in more than $357,000 in salary and benefits in 2013.
Peter Watson, the top civil servant who works for Redford's cabinet, was the top money-earner among mandarins at $342,000 in base salary.
The numbers showed that deputy ministers — the top civil servants in each department — earned salaries ranging in the low $200,000s to just over $300,000.
"Quite frankly it is important to compensate people appropriately. I'm not going to get into negotiating or discussing individual contracts," Redford said .
"It's a very competitive economy in Alberta. People are well compensated. Many of the people who work in the government of Alberta are paid more than in other jurisdictions across the country and that will continue."
— With files from Dean Bennett in Edmonton
Follow @BillGraveland on Twitter.
Also on HuffPost