The Ukip leader told Channel 4 News that he could be accused of "sour grapes" or laughed at if he complains about allegations the Conservatives spent more than double the legal limit to campaign for the seat that he lost out on in 2015.
"I have no doubt that what happened in that Thanet constituency was in complete breach with electoral law," Farage told host Jon Snow.
Farage: 'Wholesale disregard for the law'
Farage agreed that the Conservatives had "swindled" the election, in which he came second to the Tory candidate Craig McKinley, who won with 18,838 votes to Farage's 16,026.
But he confirmed that neither he nor his party would be submitting a complaint to the Electoral Commission, and Ukip's only MP Douglas Carswell won't raise the matter in the House of Commons.
Snow repeatedly challenged Farage over why he would not complain, saying it was his obligation and chance to be "the agent of reforming Britain’s democratic process”.
But Farage rebuffed him, saying he had been "laughed at" when he previously raised concern about election overspending.
Farage lost to the Conservatives by 2,000 votes
He claimed he had tried to raise the issue in "by-election after by-election" but had been laughed at.
“I tried at Newark. I said the Tories had completely overspent, and I was called a bad loser,” Farage said, referencing the seat where the Tories beat Ukip in a by-election and have now also been accused of overspending.
“I think if the party is complaining about [something involving] itself, they say it’s all sour grapes,” Farage said.
Snow asked if Farage was only holding back from complaining because Ukip was also guilty of overspending in elections, to which Farage hit back: “Are we complaint? Yes. But do I want to be seen to be a whinger - no.”
"I’ve got a referendum to fight. I don’t look backward, I look forward,” Farage told Snow.
Channel 4 News has uncovered bills that it claims show the Tories could have incorrectly declared spending for the Thanet South election, which was "probably the most fiercely-fought of all constituencies at last year's General Election".
The Conservatives appear to have spent more than two and a half times the legal spending limit of £15,016 per constituency in the campaign, it reported.
Snow asked Farage why he won't complain
The broadcaster claims to have seen bills for Conservative party spending of more than £14,000 at a hotel in the Thanet South constituency, where senior Tory figures stayed. They were not included on the form, and neither was a bill for more than £4,000 at another hotel, not in Thanet South by nearby, covering stays from top Tory campaigner Marion Little.
In response, the Tories told Channel 4 News that these costs weren't included in its local campaigning expenses because they were filed as "national spending" and the staff who stayed worked on campaigns across the country.
Other "questionable" Tory expenses, according to the investigation, were adverts in local free papers in Thanet, also declared to the Electoral Commission as national expenses. But Channel 4 News claims it has taken legal advice that said these spends should have been classed as local expenses.
Farage accused Labour and the Tories of a "pact" to ignore each other's overspending in elections, saying he was "entirely confident" that this was happening.
He said that although he wouldn't complain, he was confident that "members of the public" would.
“Perhaps I’ll be laughed at a bit less now that these Channel 4 reports have come in," he said.