Guy Aubert, who resigned as CVTech's director on January 24, issued a letter to shareholders on Monday that detailed two previous takeover bids. The letter was made public on Thursday.

CVTech's shares rose 20 percent to C$1.48 on Friday before trading was halted.

The company said the offers were inferior according to a committee it set up in 2012 to review such alternatives.

The first offer of C$1.65 per share in January represented a 45 percent premium to the stock's previous closing, while the second offer in March, at C$1.95 per share, was at a 70 percent premium, Aubert said in his letter to shareholders.

"At the very least, shareholders should have been informed and allowed to decide whether or not the company should be sold," Aubert said, terming the offers "significant".

The company also said on Friday it received the first takeover bid from the electric contractor in December 2011. The suitor withdrew the offer after CVTech decided to solicit offers from other interested parties, it added.

CVTech, which has a market value of C$88.18 million ($85 million), provides construction and maintenance services to public utilities and heavy industrial markets in Quebec, Ontario and eastern United States.

Aubert also urged the shareholders to reject several bylaw changes at CVTech's annual meeting on June 4. Gestion G. Aubert Ltée, the firm controlled by Aubert, had attempted to replace the board last year.

(Reporting by Krithika Krishnamurthy in Bangalore; Editing by Don Sebastian)