Serial sexter Anthony Weiner has been whacked with big fines for the improper use of 2013 mayoral campaign funds — including to pay for a personal cell phone.

An audit by the Campaign Finance Board found that Weiner’s campaign committee expensed two mobile lines — one of which the disgraced pol said was used for fundraising.

But auditors concluded that “because this line remained the Candidate’s personal phone from May-September 2013, its usage is presumed to be personal.”

The CFB hit the campaign for that and other irregularities to the tune of nearly $65,000 in penalties.

The board also ordered the committee to repay the $195,377 in funds that remain in Weiner’s 2013 campaign account – which are considered public cash.

The depletion of that account could put Weiner in the awkward position of having to go hat-in-hand to raise additional funds to cover the fines – or else pay for them out of his own pocket.

Candidates are personally liable for all penalties assessed on their campaigns, according to the CFB.

The bulk of the fines came from the campaign’s failure to explain tens of thousands of dollars in expenses during the campaign and more than $100,000 afterward – including to a consultant.

The tab for the improperly expensed mobile lines and dry cleaning bills added up to $1,539.

A spokeswoman for Weiner’s campaign – which received $1.6 million in taxpayer matching funds in 2013 – didn’t immediately respond to a request for comment.

In 2013, Weiner’s entry into the Democratic primary shook up the race for City Hall – at least temporarily.

His bid was derailed after he admitted in July 2013 that he hadn’t quit the damaging sexting behavior that had knocked him out of Congress two years earlier.

Weiner ended up with less than 5 percent of the vote in the Democratic primary.

In August, Weiner’s wife – Hillary Clinton aide Huma Abedin – announced she was separating from her husband after yet another disclosure — that he was sexting a 15-year-old girl.

Weiner only recently returned to the city after a stint in a Tennessee rehab facility for sex addiction.

Anthony Weiner’s embarrassing sexting scandal is as pathetic as he is: