Upper West Side parents are challenging a successful charter-school network’s expansion into their high-performing district, saying it wants to use space in a public-school building that doesn’t have enough room.

They’re also questioning SUNY’s process for approving the West Side Success charter school, which hopes to join former Councilwoman Eva Moskowitz’s Success Charter network.

“She hasn’t even been approved yet, and she’s advertising?” said Noah Gotbaum, president of the district school board.

He called that “a complete disregard for the legislative process.”

But local resident Debra Warren said the charter would give her more options.