Beware, New York: Public Advocate Jumaane Williams is mooching off the public, pocketing nearly $1 million in taxpayer funds for a reelection campaign he has locked in.

The Campaign Finance Board says he’ll get at least $959,093 in public matching funds, though his opponent qualified for none. The board has to grant eight bucks for every dollar raised by small private donations, provided the candidate raises enough to qualify.

So Williams pockets a windfall that he’ll likely use to boost his profile for another race he’s eyeing — challenging Gov. Kathy Hochul in next year’s Democratic primary.

State Conservative Party Chairman Jerry Kassar has it right: Public funding of campaigns is “an opportunity for politicians to obtain taxpayer dollars and utilize it in a manner that is not related to the campaign they’re running for.”

Williams’ lame excuse: The free money will ensure New Yorkers hear his “message.” But his real message is plainly that anything’s OK as long as it feeds his personal ambition.