The science agency will shed another 18 Hobart-based jobs by the end of the month, bringing the number of job losses at the site over the past year to 67.

The redundancies are the first since the federal government slashed the organisation's funding by $115 million in the budget.

The CSIRO last month announced at least 500 workers across the country would go in response to the funding cuts, with Hobart expected to be among the hardest hit sites.

Community and Public Sector Union state secretary Jessica Munday said the organisation was being forced to scale back and reshape many of its research areas.

``With a budget reduction of $115 million, the CSIRO will have to keep cutting jobs,'' Ms Munday said. 

``We don't know as yet how many more jobs will go, but we expect there will be more cuts into the future.''

Mr Wilkie said the budget cuts were contained in appropriation bills set to come before Federal Parliament in coming weeks, and he urged others to join him in voting against them.

``I'm very critical of the Abbott government for making the cuts but I'm equally critical of Labor and the Greens for being all talk and little action,'' Mr Wilkie said.

``If they're fair dinkum about saving these jobs, they will block the appropriation bills.''

Greens leader Christine Milne said her party had been the strongest supporter of the CSIRO for decades, and would continue to be. 

But Senator Milne said blocking the bills would have serious consequences, grinding government services to a halt by cutting off pay to public servants.

``I can assure the Australian people the Greens will be blocking the cruelty of this budget,'' Senator Milne said.

``There will be multiple double-dissolution triggers and we are ready to fight an election on Tony Abbott's brutal budget.''

A spokeswoman for Industry Minister Ian Macfarlane said the government was committed to ensuring CSIRO remained a world-leading scientific institution.