"It's time for him to step up, take full responsibility and resign," said Andrews.
CBC News has obtained a bank deposit slip that suggests construction company Pennecon donated $5,500 to Penashue's federal election campaign in 2011.
That was the same as the total amount of money donated by six Pennecon executives who were each given tax receipts for their donations.
Corporate campaign donations are illegal in Canada.
Penashue won his Labrador seat by just 79 votes.
Bob Rae, interim leader of the federal Liberal Party, has called on the federal elections commissioner to investigate the donations, as well as campaign overspending and flights that an airline wrote off for Penashue during last year's election campaign.
"This is another example where he didn't play by the rules, he cheated, he bought the election and nothing less than a byelection right now is acceptable," said Andrews.
Late Thursday, Pennecon issued a statement that said the company had been in contact with Elections Canada, and will conduct its own internal review.