A fourth person was arrested in the Western Cape on Thursday in connection with tax fraud of more than R30-million, police said.

The Hawks arrested the 46-year-old man from Welgemoed at Cape Town International Airport, said Inspector November Filander.

A group of individuals and business owners allegedly targeted major commercial banks with fraud related to VAT, custom and excise.

The fraud had a potential value of "as much as R800-million", police said.

Police searched nine houses and businesses last Thursday and confiscated computer equipment as well as documentation following a joint investigations between the Hawks' commercial branch and the South African Police Service.

Two men and a woman were arrested and were due to appear in court last Monday.