The Independent Police Conduct Authority has received a complaint about police handling of the original investigation into the allegations of embattled National MP Todd Barclay's involvement in a secret taping scandal.

Last week police re-opened the case and authority case resolution manager Sarah Goodall said the complaint about the original investigation was received on June 21, sparked by renewed media interest in the case.

It came from someone not personally involved in the case and was thus classified as a "principled complaint," Goodall said.

FAIRFAX NZ PM Bill English's eventual public admission that Barclay had made the recordings, which English relayed in his own police statement in April last year, appear to have opened the door for police to resume their investigation.

"We are currently assessing information in accordance with our normal processes and determining what, if any, action to take," Goodall said.

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Barclay was forced to withdraw from contending his Clutha-Southland seat at the September general election, in a cloud of controversy amid allegations he made secret recordings of electorate staffer Glenys Dickson, and a brain-fade from Prime Minister Bill English who momentarily forgot Barclay had admitted making the recordings to him.

Barclay refused to co-operate with the original police investigation more than a year ago, which left it to stagnate with police saying they did not have enough evidence to issue warrants and obtain the recordings.

But English's eventual public admission that Barclay had made the recordings, which English relayed in his own police statement in April last year, appeared to have opened the door for police to resume their investigation.