The American Samoa Power Authority says the US Department of Labor is "inaccurate" in saying it underpaid workers' overtime.
The authority's acting executive director, Wallon Young, said the utility paid out approximately $US110,000 to 180 employees for time clock violations over three years.
The workers got an extra $US611 dollars on average for the three year period, he said.
But the labor department said its investigators found the authority "altered employees' time records to cap shifts at eight hours each day, regardless of the number of hours actually worked".
Mr Young said the federal agency's "statement is inaccurate".
He said timekeepers would deduct "early" clock-in and "late" clock-out minutes when preparing time sheets, reflecting actual hours worked.