Wynn Resorts is looking to unload its online sports-betting business at a steep discount as the fledgling niche faces painful losses from stiff taxes and costly promotions needed to lure customers, The Post has learned.

The Las Vegas-based casino giant is quietly shopping its Wynn Interactive unit — operator of the WynnBet online gaming app — and has slashed the asking price to $500 million after floating a $3 billion valuation less than a year ago, a source close to the situation told The Post.

The fire sale comes less than six months after Wynn was publicly readying a splashy spring launch for WynnBet, signing up NBA legend Shaquille O’Neal as a brand ambassador.