Australia’s peak science body is bracing for a May budget cut of up $150 million, or more than 20 per cent of its total government funding.

Fairfax Media can reveal the CSIRO’s top executive team has been modelling a range of scenarios that would see the scientific agency lose up 20 per cent of its $757 million a year funding. Some in the agency's upper echelons expect funding will be cut by 10-15 per cent or by $75 to $110 million. It is expected the federal government's Commission of Audit will recommend big savings.

CSIRO chairman Simon McKeon acknowledged the organisation was preparing its response to different budget scenarios. ‘‘We’ll all be biting our nails in the lead-up to the budget," he said.

It is understood the CSIRO has not finalised its operational budget for the next financial year and is waiting for the May budget in a further sign the agency expects a big hit. CSIRO receives about 60 per cent of its funding from the federal government.