The government faces an uphill battle to realise its plans to oversee the largest expansion of Australia’s military since the Vietnam War.

Prime Minister Scott Morrison announced on Thursday that permanent Australian Defence Force personnel would be increased from nearly 60,000 to almost 80,000. The broader defence workforce is planned to expand to over 100,000.

The announcement is part of a heightened, pre-election focus on national security and the release earlier this week of plans to build an operations base for a not-yet-built fleet of nuclear submarines.

Plans for a fleet of nuclear submarines are part of the government’s push to increase national security. Photo: Getty

“[The government has] always been clear-eyed about the threats and the environment that we face as a country, as a liberal democracy in the Indo-Pacific,” Mr Morrison said.

The new funding will grow the size of the ADF by about 30 per cent, beginning from the 2024-25 fiscal year, with a significant proportion hired as part of the submarine program.

But it is clear that certain branches will find it difficult to meet the quota.

The strength of the jobs market means the army has consistently struggled to meet the required supply of trained recruits over the past two decades.

Another issue facing the army especially is a top-heavy command structure and a comparatively slim ratio of top brass to frontline forces.

Clive Williams of the ANU’s Strategic and Defence Studies Centre noted that the increase in numbers would be welcomed by the defence force in the current national security environment.

But he said that any additional personnel should go towards combat areas.

“Our deployable combat force is pathetically small compared to the total number of personnel in the ADF and the size of the overall defence budget,” Professor Williams said.

Labor accused Mr Morrison of making national security an election issue and suggested that he had been holding onto Thursday’s announcement for months.

Shadow minister for defence Brendan O’Connor said Labor backed the increase, but doubted the government’s “track record on recruitment and retention”.

“The government has waited until the eve of an election to make yet another announcement that won’t take effect for 18 years,” he said.

Earlier, Mr Morrison had defended the 2040 end date for the plan to boost recruitment.

“You can’t flick a switch to increase your army, navy and air force overnight,” he said.

Defence Minister Peter Dutton earlier attacked Labor’s history on national defence and implied that the increased recruitment was made necessary because of a growing regional threat from China.

“If people think that their ambitions within the Indo-Pacific are restricted just to Taiwan and there won’t be knock-on impacts […] they don’t understand the lessons of history,” Mr Dutton said.

Opposition leader Anthony Albanese pledged on Thursday to keep defence spending at levels above two per cent of the national budget in an address to the Lowy Institute.

The troop buildup announcement comes on the same day an inquiry has been told of a failure of leadership to address cultural problems in the defence forces.

Australia’s Air Force chief, Air Marshal Mel Hupfeld, told the Royal Commission into Defence and Veteran Suicide that the “lion’s share” of people within the Defence Force do the right thing.

But he admitted there have been – and possibly still are – people not performing according to the values of the ADF.

The commission has previously heard hazing, stigmatisation over seeking help, bullying, and a culture of silence around sexual assault and domestic violence have been consistent themes within the defence force.

Air Marshal Hupfeld said people are recruited based on their values and how they will integrate with the air force.

“I wouldn’t assume there are ‘unofficial values’ (in the ADF),” he told the commission on Thursday.

– with AAP