The Independent Police Conduct Authority is looking into the police investigation into National MP Todd Barclay.

Police last week re-opened their investigation into allegations the Clutha-Southland MP secretly recorded staff in his Gore electorate office.

The original investigation was dropped after 10 months when officers cited a lack of evidence for a successful prosecution.

IPCA spokeswoman Sarah Goodall says they received a complaint on June 21 regarding police handling of the matter.