Republican candidate for governor Rob Astorino derided Gov. Andrew Cuomo’s video presentation at the Working Families Party convention on Saturday as a “hostage tape” and questioned the agreement that gave the Democratic incumbent the party’s endorsement.

“I don’t know if you notice him blinking, but that was an SOS,” Astorino joked in a Talk-1300 interview with The Post’s Fred Dicker. “It looked like a hostage tape.”

Cuomo on Saturday was endorsed by the labor-backed WFP and at the same time announced his support for a Democratic takeover of the Senate, as well as a package of liberal measures including the public financing of political campaigns.

Republicans have said the deal is legally questionable.

“It clearly is a quid pro Cuomo,” Astorino said. “If it’s not, I don’t know what is.:

Astorino, who has the backing of the state Conservative Party, also knocked Cuomo for shifting his agenda in order to shore up support among the liberal base of the party.

“I know it smells, I know it stinks and it seems to me that by making this deal with the Working Families Party and public embracing the Bill de Blasio agenda, Andrew Cuomo just signed the death warrant for New York state,” Astorino said.