Christchurch Police have charged a third person in relation to powerline tampering, copper and electrical thefts in the city

Officers were called to Bromley's Ruru Road just over two weeks ago, where a man allegedly stole a vehicle loaded with electrical supplies.

He was later arrested after it was found on Portman Street.

It follows the arrests of two people caught tampering with powerlines a week earlier.

Senior Sergeant Roy Appley says officers continue to investigate these recurring incidents.

He says the arrested trio aren't the only ones involved in this activity -- and caution scrap metal dealers to be weary of frequent customers.