Former speaker of the US House of Representatives Dennis Hastert was sued by a man for US$1.8 million (AU$2.33 million) plus accrued interest days before he is slated to face sentence for a felony banking crime. According to the unidentified man, Hastert owed him the money for hiding a case of sexual abuse during the days when the former speaker was a wrestling coach in Illinois.

The breach-of-contract lawsuit, filed in Kendall County on Monday, alleged that Hastert promised to pay the man an amount of US$3.5 million (AU$4.54 million) for keeping a deal strictly confidential.

The man, who was referred to as Individual A in the court documents, was sexually abused by Hastert at a wrestling camp when he was 14 years old. The former speaker was then a wrestling coach at the Yorkville High School in Illinois.

Hastert, 74, who pleaded guilty to illegally structuring bank withdrawals last year, was purportedly using the money to pay to Individual A. But he had to cease the payouts after the federal government began pursuing the case, the New York Magazine reported.

The court documents said that Individual A suffered from panic attacks that caused “periods of unemployment, career changes, bouts of depression, hospitalisation, and long-term psychiatric treatment.” But the man never connected those problems to the abuse by Hastert until 2008 when he came to know that Hastert had also molested someone else, the Chicago Tribune reported.

Hastert’s attorneys said they have nothing to comment on the lawsuit.

Hastert can face up to five years of imprisonment when he is sentenced on Wednesday. But his plea agreement with the prosecutors calls for facilitating a sentence of not more than six months.

The former speaker pleaded guilty in October to one count of illegally restructuring bank withdrawals. He admitted in a plea agreement that he paid Individual A an amount of US$1.7 million (AU$2.20 million) in cash to keep secret an unspecified misconduct that happened decades earlier.