What institution(s) has the power to impose non-criminal sanctions for campaign finance infractions?

Omnibus ElectionCode

Sec. 57.Measures to ensure enforcement. - For the effective enforcement of theprovisions of this Code, the Commission is further vested and charged with thefollowing powers, duties and responsibilities:

    To inquire into the financial records ofcandidates and any organization or group of persons, motu proprio or uponwritten representation for probable cause by any candidate or group of personsor qualified voter, after due notice and hearing.

For purposes ofthis section, the Commission may avail itself of the assistance of theCommission on Audit, the Central Bank, the National Bureau of Investigation,the Bureau of Internal Revenue, the Armed Forces of the Philippines, theIntegrated National Police of the Philippines, barangay officials, and otheragencies of the government.

Source: http://www.comelec.gov.ph/?r=References/RelatedLaws/OmnibusElectionCode/OECArt7