Estimates to protect the Chignecto Isthmus between New Brunswick and Nova Scotia have ballooned to $650 million.

The new figure comes ahead of Wednesday’s deadline to apply for federal funding for the infrastructure project.

Speaking with reporters on Tuesday, New Brunswick Premier Blaine Higgs said he expects that number will change again.

“I wouldn’t be surprised to see it increase further and that’s why it’s important in an application that we recognize that there’s some variability in an estimate that’s still somewhat in a preliminary basis,” said Higgs.

A network of dykes and aboiteaux originally installed in the late 1600s currently protects communities, infrastructure, private lands and natural resources.

But rising sea levels and frequent severe weather events threaten the stretch of land, considered a vital transportation link.

Proposed fixes include raising existing dikes, building new ones, or raising the dikes and installing a steel walls at select locations.

The premiers of both Maritime provinces confirmed Tuesday that they intend to apply for federal funding under the Disaster Mitigation and Adaptation Fund.

Ottawa has said it would cover up to 50 per cent of the total costs, but the premiers said the federal government should cover all of it.

“This is a nationally significant trade corridor. $35 billion worth of trade flows across that corridor every year,” Nova Scotia Premier Tim Houston said on Tuesday.

As the premiers apply for funding, they are also threatening to take the matter to court to force the federal government to pay the full cost.

But federal infrastructure minister Dominic LeBlanc maintained he believes any lawsuit would be a waste of money.

“I’ve said consistently, and I’ll repeat it again, that this is a priority project for us,” LeBlanc said on Tuesday. “We look forward to working with the province.”