Malcolm Turnbull says he is weighing up a Nato request to send more Australian troops to Afghanistan.

The prime minister, who visited the region ahead of Anzac Day, confirmed he has been asked for additional personnel to help deal with a resurgent Taliban and the continuing threat from Islamic State fighters.

In April, as many as a dozen militants stormed the largest army base in northern Afghanistan, killing at least 140 soldiers, many of them unarmed, in what was the largest Taliban attack on security forces since 2001.

Afghanistan’s security forces already struggle with a high attrition rate and recruitment problems. More than 6,700 soldiers and police were killed last year, a record high.

“We are certainly open to increasing our work there, but we’ve obviously got to look at the commitments of the ADF in other parts of the region and indeed in other parts of the world,” Turnbull said.

“But it is very important that we and our other allies in the effort in Afghanistan continue to work together to build up the capacity of Afghanistan’s own security forces so that they can keep that country secure from the threat of terrorism, both ISIL (Isis) and of course the Taliban.”

More than 1,700 Australian defence force personnel are deployed in the Middle East, with about 750 in Iraq and Syria and 270 in Afghanistan. Since 2002, 42 Australian troops have been killed in Afghanistan and two in Iraq.

Kim Beazley, the former defence minister, Labor leader and ambassador to the US, told Fairfax Media the request was uncontroversial.

“We have a lot invested in that Afghan operation so I imagine the Turnbull government would be looking at [the request] pretty favourably,” he said. “I would hope they would look on it, given the context, of being within the framework of what we’re already doing. I think we’d probably want to do it.”

Outgoing defence secretary Dennis Richardson said anyone who went into Afghanistan in 2001 should have realistically expected Australian troops to remain there for a long, long time.

“I think that is what the coalition is doing. That is sensible,” Richardson told the national press club in Canberra on Friday.

“We have now moved beyond the involvement in the direct fighting phase. We are now placing emphasis on building the Afghan forces themselves and that will take a long, long time.”

Australia must also brace for providing financial aid to Afghanistan for many years to come.

While Iraq can earn upwards of $30bn depending on the price of oil, Afghanistan has a total income from within its own domestic sources of less than $3bn a year.

“It costs over $4bn a year to keep the Afghan national security forces in operation, apart from other things that we need to assist the Afghanis with,” Richardson said.