AAP 
 
Australian patients could suffer under the federal government's changes to the Pharmaceutical Benefits Scheme, the peak doctors body says.

The Australian Medical Association is urging the government to reverse its decision to delay new listings to the PBS - a decision it made in February because of budget constraints.

Under the old system, medicines costing the government less then $10 million to subsidise got the go-ahead automatically if approved by an independent expert committee.

But cabinet now gets to delay consideration of all new drugs regardless of whether they've received the tick from the Pharmaceutical Benefits Advisory Committee (PBAC).

AMA president Steve Hambleton, who spent two years on the committee ending in 2009, said the delay had already created a backlash among big drug companies.

A number of major pharmaceuticals have written to a Senate inquiry set up to investigate the changes, warning of a slide in investment and that it will take longer for new drugs to get to Australia.

Dr Hambleton said it was a big concern, and one the government had itself invited.

"We actually suggested to the government that if they proceeded with this change it would invite a political response," he told the National Press Club on Wednesday.

"This is really a political response if the companies are saying we are thinking of downgrading Australia's priority in our rolling out of our drugs."

The Senate inquiry, put forward by the coalition, was set up in June to examine how the government administrates its PBS, and is due to report back in August.

So far it has received 52 submissions, including those from major pharmaceutical companies, such as Pfizer, GlaxoSmithKline, Janssen-Cilag and AstraZeneca.

All said the government's decision had created uncertainty for the sector, which would factor in future decisions to hold clinical trials in Australia or to put new drugs on the market.

"The end result being that Australian patients will have to wait longer to access medicines," AstraZeneca's submission reads.

The companies also argued that the government was undermining its own PBS by dismissing the recommendations of the PBAC and criticised the new system as a method of saving money.

Janssen-Cilag noted that one of its drugs delayed for consideration - Sustenna - would add just under $3 million to the PBS in 2011/12 and just over that amount in 2012/13.

The cost was modest given the potential benefits for Australians suffering from schizophrenia, the company said.

Dr Hambleton said he understood the government's budget constraints, but stressed that the PBAC also considered cost implications when assessing new medicines.

"It's one of the most rigorous ways of actually looking at cost-effectiveness," he said.

"The reality is we are greatly concerned that drug companies may downgrade Australia.

"We may not get innovations until much greater in the cycle and our patients will suffer."