The CSIRO (Commonwealth Scientific and Industrial Research Organisation) Co-operative Credit Society Limited was registered in Victoria on 19 September 1957.

Interest in establishing a credit union in the Melbourne offices of the CSIRO had been piqued by the 1954 establishment of the Laboratories Credit Union by Sydney based CSIRO staff. The impetus to start a Victorian based credit union had strong support from senior CSIRO personnel (including Sir Ian Clunies Ross, the CSIRO chair at the time) and also the Victorian Branch of the CSIRO Officers’ Association.

Two board meetings were held in early September 1957 and appointments were made to the roles of Chairman (Walter Ives), Secretary (Ivan Carrucan) and Treasurer (Jack Bourne). The first 40 members were admitted on 15 October 1957. The initial membership bond was limited to officers and employees of CSIRO aged over 18 years.

The credit society steadily grew and by the end of 1966 it had over 1770 members and more than $950,000 in deposits.  In 1966 Joel Belkin was appointed the first full-time general manager (a role he held from 1966 until 1981). In 1968 payroll deductions were introduced and this streamlined the repayments of loans by members.

In 1982 the credit society joined the Victorian Credit Co-operatives Association (VCCA), which was the peak body for over 140 Victorian based credit unions.

Following a period of negotiation, the Board of the Canberra based Laboratories Co-operative Credit Union Limited agreed to amalgamation with the CSIRO Co-operative Credit Society Limited. The amalgamation occurred on 26 January 1986.

CSIRO Co-operative Credit Society first used the name Sirocredit for marketing and branding in 1986. Sirocredit continued to grow and by 1988 it had more than $47 million in total assets and served more than 7,500 members throughout Australia. In 1994 a new logo and trademark was registered for Sirocredit.

In 1997, Sirocredit celebrated its 40th anniversary by commissioning an in-depth history entitled Sirocredit: The First 40 Years, 1957-1997, by Brian Carroll. The foundation chair Walter Ives wrote in the book’s foreword that “We saw the Society as a means of channelling resources, mostly from older officers, with money to invest, to younger officers, facing the usual stresses of proving for a family.”

The next two decades saw considerable change for the organisation. On 1 July 1998, Sirocredit merged with Enterprise Credit Union Limited and Outlook Credit Union Co-operative Limited to form Members Australia Credit Union Limited. In 2003 Members Australia Credit Union merged with Education Credit Union to form Members and Education Credit Union (mecu). In 2011 mecu began trading as bankmecu and in 2015 it commenced trading as Bank Australia.