Wakefield's Conservative party has been fined £200 by the Electoral Commission.
The organisation failed to file its 2017 statement of accounts on time.
In a statement on Wednesday, the Commission, the independent body which oversees the conduct of election parties and candidates, said the local group had paid the fine last month.
Wakefield Conservative Association chairman David Hopkins said that the error had occurred as a result of information arriving late from one of its ward branches.
"The accounts were filed around nine or 10 days late beyond the deadline," he said.
"It shouldn't have happened and the ward was certainly being chased up by our treasurer, but for one reason or another they didn't get it to him.
"I think it was because somebody was away at the time. There was nothing underhand about it being late.
"Obviously when we put the accounts in, the association was told it might result in a fine.
"A letter of explanation was sent to the Electoral Commission, which was accepted, but nevertheless they said they'd be imposing a fine."
Mr Hopkins would not say which ward was responsible but added that measures had been put in place to ensure it would not happen again.
Local Democracy Reporting Service