Gov. Andrew Cuomo announced a $1 billion plan Thursday to expand the city’s main convention center, which just a few years ago he wanted to replace with a massive new complex near Kennedy airport.

Cuomo, a Democrat, said construction would start this year at the Jacob K. Javits Center on Manhattan’s West Side. Plans call for adding 344,000 square feet of meeting and exhibition space, 400,000 square feet of operational space and 479,000 square feet for delivery truck parking.

Cuomo made the announcement four years after he proposed razing the Javits Center and replacing it with a $4 billion convention center in Queens between the city’s major airports.

In his 2012 State of the State speech, Cuomo called the Javits Center “obsolete and not large enough to be a top-tier competitor in today’s marketplace.”

On Thursday, he called it the busiest convention center in the country but added, “like anything else, it’s a competitive industry, more convention centers are coming on line and if you want to remain competitive you have to grow and you have to increase and stay ahead of the competition.” He did not take questions.

The Javits Center was completed in 1986 and was named after U.S. Sen. Jacob K. Javits, a Republican who died that year. It’s run by the New York Convention Center Operating Corporation, an entity created by the state Legislature to maintain it and collect revenues.

Cuomo said the expansion would be paid for with existing Javits Center funds.

“Not only is this a plan and a vision but it is going to happen,” he said. “Government has gotten too good at announcing plans that never actually materialize. I am in the opposite business.”

The Javits expansion was the latest in a series of public works projects Cuomo has announced in the last week, including a Penn Station renovation and a new Long Island Rail Road track.

Javits Center officials say it hosted 177 events and more than 2 million visitors in 2014, generating an estimated 478,000 hotel nights.

But Cuomo and others have long complained that the Javits Center was losing business to newer, larger convention centers in other cities.

“We’ve watched cities like Chicago, cities like Orlando (Florida) build massive state-of-the-art convention centers that can attract conventions that we cannot,” said Peter Ward, president of the New York Hotel and Motel Trades Council, who attended Thursday’s news conference at the Javits Center. “Every convention we lose is lost revenue.”

But a writer on the subject of convention centers says convention and trade show attendance at the nation’s four largest convention centers — those in Chicago, Orlando, Atlanta and Las Vegas — has fallen since 2000.

Heywood T. Sanders, a University of Texas at San Antonio professor and the author of “Convention Center Follies: Politics, Power, and Public Investment in American Cities,” said convention centers have been oversold as agents of economic growth.

“Spending a billion dollars and building yourself more space is a great way to get more construction jobs and a lousy way to get more convention business,” Sanders said.

Photo Credit: New York Governor Andrew Cuomo speaks during a news conference at the Javits Convention Center in New York, N.Y., Thursday, Jan. 7, 2016. Seth Wenig / Associated Press