It appears the estimated cost of redeveloping LaGuardia Airport has climbed by about $1 billion.

According to an agenda released by the Port Authority of New York and New Jersey Friday, the redevelopment of the Terminals C and D will cost $4 billion — $1 billion more than Gov. Andrew Cuomo has previously announced. Delta Airlines, which is leasing the terminals, is currently in the early stages of designing the new terminals.

At the groundbreaking for construction at Terminal B last month, Cuomo announced the total project — the redevelopment of terminals B, C and D — would weigh in at an estimated $7 billion, with Delta’s terminals accounting for roughly $3 billion of the bill. Representatives for the governor could not immediately be reached for comment.

The agency will contribute up to $600 million to the construction of these terminals, which will connect to Terminal B, according to agenda documents for next week’s meeting. Port Authority is expected to vote on its contribution to the project on Thursday.

Cost changes for major infrastructure projects are fairly common — one extreme case is the World Trade Center Transportation Hub, whose final tab was at least double its $2 billion estimate.

The price tag attached to the airport’s redevelopment has been a sore spot for some Port Authority board members. At a meeting in March, a few of them squabbled over whether the cost of the Terminal B redevelopment would cost $4 billion or $5.3 billion — the discrepancy hinging on whether or not previous work done onsite should factor into the total projected bill.

Officials have long touted the project as one of the biggest private-public partnerships in the country, since a majority of the project is funded from private resources. LaGuardia Gateway Partners — which includes Skanska, Vantage Airport Group and Meridiam Infrastructure — is designing, building, financing and operating the first phase of the airport project, the demolition and rebuilding of Terminal B.