The practice was first established in Forster in the early 1960's. In 1969, Gordon Riddell took over and operated the practice until August 1977, when it was disposed of by his widow to Dempsey Baker & Berry. In January 1979, the partnership of Dempsey Baker & Berry dissolved and Brian C Baker operated as a sole practitioner until July 1987, when the partnership of Baker Harrison & Main was formed.
In April 1989, Brian unfortunately passed away and the remaining partners of Ross Harrison and Jim Main continued the partnership until July 1995, when Andrew McArthur was admitted as a partner and the current name of Harrison Main & McArthur was established. This partnership continued to operate until the retirement of Jim Main in September 1998 and the admission of Rod Northey as a partner on the 1st October 1999.
From 1 July 2013, the business changed its name to HMM Accountants & Business Consultants, a Chartered Accountancy firm.