Sen. Dave Thompson, R-Lakeville, said there’s a simple reason he did not report income he received from the state’s Republican Party.

“Independent contractor income is not to be disclosed by candidates,’’ Thompson said. And the $70,000 he was paid as a “consultant’’ by the GOP was as an independent contractor.

Monday morning, the DFL Party announced that it had filed a complaint against Thompson for failing to report the income he received from the party between October 2009 and November 2010.

Late Monday afternoon, Thompson, an attorney and a former talk radio personality, responded to the complaint.

“I started work as an independent contractor on Oct. 1, 2009,’’ Thompson said in a statement. “Of course, the fees paid to me were fully disclosed by the Party as required by law, and therefore were public knowledge.’’ (There is some question as to whether the GOP reported many payments, including those to Thompson, in a timely fashion.)

In his statement, Thompson cited the disclosure form. “The form specifically states, ‘do not include payments for services as an independent contractor, social security payments, unemployment compensation, workers’ compensation, pension benefits, income from rental property or insurance benefits.’’’