State Republicans wrapped up their disastrous convention in Midtown yesterday facing costly and divisive primary fights in races for three of the state’s top posts, including the governor’s office and both US Senate seats.

Unable to rally behind a single candidate, delegates allowed both former Nassau County lawmaker Bruce Blakeman and conservative economist David Malpass to seek the party nod against Democratic Sen. Kirsten Gillibrand.

Hours earlier, Buffalo real-estate mogul Carl Paladino attacked GOP standard-bearer Rick Lazio for taking bonuses as a JPMorgan lobbyist and announced he would spend half a million dollars to petition his way onto the party ballot for governor.

The party opened its gathering at the Sheraton New York Hotel & Towers Tuesday by approving a primary between little-known CIA veteran Gary Berntsen and lesser-known political consultant Jay Townsend in the race against Sen. Charles Schumer.

“These are great candidates, and we know they know who the enemy is: It’s not each other; it’s Senator Gillibrand and Senator Schumer,” state Republican Chairman Ed Cox told delegates.