Security experts have broadly backed Australia's modest increase of 30 military trainers to help Afghanistan battle a resurgent Taliban and the so-called Islamic State though some say a more strategic approach is still needed.

After the Turnbull government announced the boost, which will take the total number of Australians to about 300, former chief of army Peter Leahy said the NATO-led coalition needed to "call out" Pakistan for giving safe haven to insurgents across the Afghan border.

His comments were echoed by former Army officer and Australian National University security expert John Blaxland, who said putting pressure on Pakistan was one of a series of moves the coalition needed to make to avoid simply piling more troops into the conflict.

Defence Minister Marise Payne announced on Monday morning that Australia would provide the troop boost in response to requests from NATO.

The total NATO increase is likely to total several thousand, on top of the 13,000 that are already there, with the US providing the bulk of the numbers. Senator Payne acknowledged there had been "setbacks" in the war-torn country.

Professor Leahy, who now heads the University of Canberra's National Security Institute, said the increase was proportionate to the need expressed by NATO commanders but stressed that it made sense only if the additional troops were in specialist training areas such as air support and logistics support.

"If it is plugging shortages in those high skill areas, then that is where you're going to get a disproportionate effect," he said.

Australia and other coalition countries had an obligation to prevent the country from toppling back into extremist-riven anarchy, he said. But he said the coalition still lacked a clear strategy. In particular, he said, the coalition had to "really take on Pakistan at a diplomatic level" for giving "support and safe haven" to the Taliban and other groups.

Professor Blaxland said the coalition also needed to tackle corruption and the opium trade for the military effort to make sense as part of a broader strategic plan.

He told the ABC that a friend of his who had recently returned from Afghanistan had said the current effort was "like ??? kicking goals in a game of cricket".

He said the US and NATO did not appear to have a "compelling game plan".

Jacinta Carroll, counter-terrorism expert at the Australian Strategic Policy Institute, said the security situation was the "worst since 2001".

She said Australia had a good track record in training local forces. The 30-person increase was a sustainable one for a relatively small national force and would make a difference, she said.