President Biden has taken advantage of the very loopholes he has criticized to avoid paying big bucks in taxes, which he now wants to hike.

In 2017, 2018 and 2019, Biden and his wife Jill, then private citizens, routed $13 million in income through two S corporations — the CelticCapri Corp. and the Giacoppa Corp. — to avoid paying taxes on the funds, Rep. Jim Banks (R-Ind.) alleged in a March 25 letter to Biden, citing media reports.

S-corporations do not pay federal income taxes, and the payroll taxes avoided in this case would have gone to fund Medicare.

Banks’ letter notes that the income funneled through the S corporations was derived from speaking fees and royalties for books written by the Bidens.

Joe Biden has penned two memoirs — 2007’s “Promises to Keep,” and 2017’s “Promise Me, Dad” — while Jill Biden is the author of the 2012 children’s book “Don’t Forget, God Bless Our Troops.”

The first lady also has authored a 2019 memoir, “Where the Light Enters,” as well as another children’s book in 2020, “Joey: The Story of Joe Biden,” the proceeds of which would not be covered under the tax returns cited by Banks.

The tax move is completely lawful, and Biden faces absolutely no legal trouble over it. But politically, it’s a different story.

Biden has spent years advocating for elimination of those loopholes, and, especially in the last decade, has been an ardent backer for of Medicare and the Affordable Care Act.

“Do you intend to undo your hypocrisy and pay these taxes back to the American people?” Banks asked in a March 25 letter to Biden.

A Biden spokesperson did not respond to The Post’s request for comment on the letter or the accusation.

Banks is part of a group of House Republicans vowing to expose the tax loopholes used by Biden in his own personal filings if he and Democrats move forward with an infrastructure package that would raise taxes.

Speaking to Fox News Monday, Banks, chairman of the Republican Study Committee, reiterated the warnings he previously delivered to the president in his letter.

“House Democrats used their oversight power to subpoena [former President Donald] Trump for his tax returns, but they’ve completely ignored Joe Biden’s abuse of our tax code,” Banks said.

“When we take back the House in 2022, Oversight [Committee] Republicans won’t forget about Biden’s legally dubious tax avoidance schemes,” he continued.

In his letter to Biden, Banks alleges that Biden used the two S corporations to avoid paying $500,000 in payroll taxes.

Banks sent the letter to Biden as the president was preparing to formally unveil half of his mammoth infrastructure package, worth about $2 trillion.

The “Build Back Better” proposal, a centerpiece of his post-COVID campaign message, will be split into two packages for Congress to consider.

The first part, focused on infrastructure, is not being well received by the far left or the right.

Despite the opposition, a top Biden official said Sunday the president was open to pushing the plan through Congress with or without Republican support.

Energy Secretary Jennifer ­Granholm suggested that the White House may pursue passing the legislation through the parliamentary procedure known as reconciliation, which requires a simple majority in the 50-50 Senate, although she added that Biden would prefer bipartisan support.

Senate Democrats used reconciliation to approve Biden’s $1.9 coronavirus stimulus plan last month.