The agreement is a four-year one, initially over two years and then extendable twice by a year at a time. The government's conservative estimate is that it needs 180 websites but it has an ambitious target of 450.

Acquia has signed the deal with the Department of Finance — the liaison for all other agencies and departments — but will use its partner network of more than 50 Drupal delivery agencies in Australia.

The company's Asia-Pacific and Japan director, Chris Harrop, was unwilling to offer any estimate of how much the contract would run to.

But a spokesman from the Department of Finance said govCMS would be offered on a subscription basis to Commonwealth Government entities, therefore expenditure against the contract would be dependent upon demand for the service.  The total contract value is up to $24 million over the life of the four-year contract.

A media release quoted John Sheridan, Australian Government CTO, as saying: "We designed govCMS to save costs while empowering agencies to act independently. We're supporting innovation by relying on Drupal, a technology proven in governments around the world."

Sheridan said work on the migration of australia.gov.au and finance.gov.au to the govCMS platform had begun.

govCMS will be broadly available to Commonwealth Government entities from February 2015.

Drupal has been used to build many government and big business sites around the world, including that of the White House.