SAN FRANCISCO — Amazon may not be the only technology giant considering a big expansion in New York.

Google is in discussions to move into a planned 1.3 million square foot office complex at the St. John’s Terminal building on Manhattan’s West Side, according to a person with knowledge of the company’s plans but not permitted to speak about it publicly.

The property, which is expected to be completed in 2022, would allow the internet giant to significantly increase its presence in the city. Google employs around 7,000 in New York, and a space that size could allow it to more than double its local work force.

The potential expansion, reported earlier by The Wall Street Journal, comes on the heels of news that Amazon appears close to building a corporate office in the city. According to two people briefed on the negotiations, Amazon is close to naming Long Island City, a fast-growing neighborhood on the western edge of Queens, as one of two locations that would together house as many as 50,000 employees.