The federal government has decided to give companies bidding on an estimated $35 billion in shipbuilding contracts for Canada's navy and Coast Guard an extra two weeks to get in their proposals.

But the National Shipbuilding Procurement Strategy Secretariat rejected a request for a two-month extension of the July 7 deadline, saying it would "be unacceptable, as it would have significant and unacceptable impacts."

HMCS Preserver, the navy's 40-year-old Halifax-based supply ship, rests at drydock at the Halifax shipyards on Thursday. (Andrew Vaughan/Canadian Press)

The bid period will now close on July 21.

The government said the two-week extension is "the maximum flexibility available to Canada without incurring costs and/or causing unacceptable impact on the NSPS program."

Four companies are in the running for the contracts, considered the largest government procurement process in Canadian history .

The two leading candidates, Halifax-based Irving's Halifax Shipyards and Seaspan Marine Inc., a bidder from British Columbia, had opposed extending the deadline.

A third competitor, Seaway Marine and Industrial Inc., is based in St. Catharines, Ont. MIL-Davie Yards Inc. in Lévis, Que., is also in the running.

One winner will be awarded the $25-billion combat vessel construction deal. Another bidder will be chosen to build the non-combat ships, which account for the remaining $8 billion of contracts initially. That order could grow to include more Coast Guard replacements.

Losing shipyards may bid on an estimated $2 billion in construction work for smaller, non-combat ships.

Mary Keith, spokeswoman for Irving, said she was disappointed that the government had decided to grant any extension.

"We've worked extremely hard and we've invested thousands of hours and significant financial resources to prepare the bid in compliance with a deadline that was established over a year ago," Keith said.

"We were ready for the July 7 deadline, we did not need an extension and although we feel the extension was unwarranted, we're going to continue our focus on submitting our bid in accordance with the new deadline."

Nova Scotia Premier Darrell Dexter said he was pleased the government rejected the two-month extension.

"The two-week extension, although not what we would have preferred, is not a significant delay in the bid process," Dexter said. "The simple fact of the matter is, we're ready to go. Our bid is ready, the Irving Shipyard is ready to comply with the original deadline. So I think it demonstrates the quality of the Irving bid, able to meet the deadlines that were set out."

"The two-week extension, I think in the big scheme of things, will not be relevant."