Grant application writing season is in full swing and deadlines loom for project funding and fellowships at the National Health and Medical Research Council and the Australian Research Council. The application success rate for major grants at the NHMRC was 19 per cent in 2013 and for ARC funding beginning in 2013 the success rate was 21.9 per cent, the lowest in at least a decade.

Australian Academy of Science secretary of science policy Les Field said he welcomed the ARC's move to offer some five-year grants, where in the past they had mostly been for three years, because Australian science was being hampered by short-term funding. But without additional government investment new ARC funding rules, released this week, would inevitably create even lower success rates among academics seeking research support.

"It is a double-edged sword - it recognises research has a long-term horizon, but we would be cautious if this resulted in fewer researchers being supported by the ARC."

Professor Field said ARC funding would need to double if it were to support all worthy applications.

It took a month or more to write a grant application and for four out of five researchers it would be a waste of time, he said. ''It's an extremely frustrating and energy sapping exercise for 80 per cent of the research population. It does take an incredible amount of time and effort to submit a grant application,'' he said.

A study from the Queensland University of Technology published in May last year found scientists spent the equivalent of 500 years' worth of time applying for NHMRC grants in 2012.

Australian Research Council chief executive Aidan Byrne said only a small number of five-year grants would be offered this year as the change was phased in.

Professor Byrne said success rates would not necessarily be affected this year and denied without extra funding the move to longer grants would mean more researchers would miss out. "The challenge here is actually switching over from a system that has a predominance of three-year grants to [a] system that might have some longer grants,'' he said. ''In either scheme the same number of researchers are supported, it's just the grants don't come up for renewal as often."

A spokesman for Education Minister Christopher Pyne, who is responsible for research funding, said he had approved more than $830 million in funding for research grants, fellowships and centres since taking on the portfolio in September. But the minister would not comment on whether there would be additional funding for research in this year's budget.