A Waikato man has been charged in relation to a suspected years-long mail-theft scheme

Police allege he used it to access people's personal information and create illegitimate documents - then used to apply for fraudulent loans and credit cards.

Sergeant Michael Palmer says a person called Police after purchases started to tally up, on a credit card that had seemingly never arrived.

He says hundreds of letters and documents were found at a Hamilton address, and they're now working to understand the extent of the offending.

The man is due to reappear in the Hamilton District Court on May 31.