A Nassau elections commissioner yesterday said his county will dump one type of electronic voting machine and go with one made by its rival company, a day before Big Apple officials are set to make their own choice between the two.

Democratic Commissioner William Biamonte told The Post he and his GOP counterpart in Nassau opted to buy Elections Systems & Software machines after using the ballot-marking device for some machines made by rival Dominion in the 2008 elections and finding problems with more than half of them.

The commissioners “felt more comfortable going with” ES & S, Biamonte said.

New York City’s 10 commissioners are scheduled to choose between the two firms today.

Dominion VP Howard Cramer said the “timing of the decisions is curious.”