Commercial advertising will be a permanent feature of the Bureau of Meteorology website and the federal government has refused to rule out running ads on other publicly funded websites.
In April the Gillard government introduced the first trial of advertising on a government website on the bureau site for one year.
But, after Prime Minister Tony Abbott and Treasurer Joe Hockey warned of steep spending cuts with the next budget, a government spokeswoman refused to rule out the spread of commercial advertising to websites such as Centrelink, the Australian Taxation Office and Australian Job Search.
''The government expects all entities to act within their remit and their responsibilities to the Australian people,'' a spokeswoman for Joe Hockey said.
Robert Crawford, a communications professor at University of Technology Sydney, said it would be a ''logical step'' for more government websites to have commercial advertising. ''In an age of government spending cuts, I wouldn't be surprised to see more of this.''
There was a danger a government could cut department budgets and require them to find funding through advertising, Professor Crawford said. ''There could be a temptation to reduce funding, but you wouldn't want them to become dependent on outside revenue because advertisers can always walk away.''
Vicki Middleton, deputy director of corporate services at the Bureau of Meteorology, refused to disclose how much the agency had received from ads. The bureau, whose budget was slashed by $13 million last financial year, has attracted big advertisers such as Telstra.
Acting opposition finance spokesman Andrew Leigh said the Abbott government failed to fulfil its election promise to ''follow due process'' by aborting the trial before its one year was up.
The bureau is one of the federal government's most visited websites, with more than 3.3 billion page views recorded in 2011.
No Victorian government websites carry commercial ads and a spokeswoman said it was ''not appropriate''.