Combining New York's primary elections would be a costly and potentially confusing development for voters as elections officials are already planning two primaries in June and August, a top state elections official in a legal brief filed this week said. 

The filing from State Board of Elections Co-Executive Director Kristen Zebrowski Stavisky was made in response to a League of Women Voters-backed lawsuit that seeks to combine New York's two primaries to a single, unified date on Aug. 23.

The primaries for the state Senate and U.S. House races were moved to August after New York's top court determined the legislative boundaries drawn by state lawmakers were unconstitutional. Primaries for the state Assembly and statewide races will remain on June 28.

Two primaries will likely cost local elections officials more money to administer and prepare for, but Stavisky argues that reversing course now and moving all the primaries to August will sow further confusion.

Test ballots for pre-election testing have been printed in most counties, as well as New York City. Early voting election ballots for the primary have also been printed. 

"If the statewide candidates were to change now, the ability of boards of elections to timely test election machines for the remaining primaries would be imperiled," she wrote in the filing. "New York requires every voting machine to be programmed then tested with paper ballots to ensure the machines are tabulating ballots correctly. This is a time consuming but crucial process to ensure election integrity. A change to the ballot requires reprogramming voting machines, reprinting ballots and retesting machines."

Elections officials have already hired more than 50,000 poll workers and have scheduled them to work for early voting and the primary day itself, and allocations for vehicle rental and transportation of equipment to the polling sites have been approved. 

And local elections are already informing voters of the primary dates through the mail. 

"New York City and other boards have engaged media campaigns to inform voters about the multiple primaries and what contests will appear at which election," she wrote. "Undoing these communications will cause massive voter confusion."