The defence minister has appointed former senior defence and security bureaucrat Dennis Richardson to conduct an urgent top-to-bottom review of the Australian Submarine Agency amid serious concerns about how it is managing Australia’s $368bn Aukus submarine contract.

Guardian Australia has confirmed that Richardson will undertake a rapid review of the agency to be completed over the next few months, focusing on the agency’s governance.

It follows the sudden resignation of one of the agency’s most senior leaders last month. As Guardian Australia reported on Wednesday, the agency’s deputy director-general responsible for program and policy implementation, David Hallinan, quit after raising concerns about how the agency was run and being dissatisfied with the response.

It also comes as the annual Australian Public Service staff census results, published last week, reveal problems within the agency with staff morale and internal communications.

The survey recorded the ASA as the second worst agency for staff wellbeing and support out of all 104 departments and agencies in the federal bureaucracy.

The finance minister, Katy Gallagher, acknowledged the census findings and suggested steps were being taken to address the problems.

“When you see areas where there are issues or problems raised … people need to respond to that,” Gallagher said on Thursday. “And I know certainly the deputy prime minister is doing that in relation to ASA.”

Dennis Richardson is a former secretary of both the defence and foreign affairs departments as well as a former head of Asio and a former ambassador to the United States.

Richardson is a member of the three-person taskforce that the deputy prime minister and defence minister, Richard Marles, appointed to oversee the implementation of the government’s Defence Strategic Review, alongside former defence minister and now high commissioner to London, Stephen Smith, and former defence chief Sir Angus Houston.

The opposition defence spokesperson, Andrew Hastie, was critical of the review.

Hastie said: “Instead of providing leadership and direction to the Australian Submarine Agency, the Albanese government has commissioned yet another review following the release of damning survey results.

“Labor must clarify when Mr Richardson’s advice is due to government, and at what price, while ensuring the delivery of Aukus is not put at risk as a result of their mismanagement.”

According to records published on Austender, Richardson has an existing $81,700 contract with Defence which is understood to cover that role and the new task is expected to fall within that, albeit undertaken solo and not as part of the trio.

Headed by V-Adm Jonathan Mead as its director general, the ASA was formed just 17 months ago to oversee Australia’s $368bn Aukus acquisition of nuclear submarines.

But there have been murmurings in recent weeks about staff unhappiness and disillusionment, culminating in Hallinan’s November resignation. Hallinan was among the ASA officials who attended the 6 November hearing of the Senate estimates committee on defence but were not called to appear because the committee ran over time.

The opposition and Greens are pressing the government to agree for the ASA officials to appear at a special spillover hearing before Christmas.

A spokesperson for Marles declined to confirm Richardson’s appointment when asked about it on Wednesday. Responding to questions from Guardian Australia, the ASA acknowledged the census findings and said it had transitioned from a taskforce to a growing agency and was working to “deliver the single biggest investment in defence capability in Australian history”.

“There are of course areas of improvement, including in change management and internal communications and we recognise this,” it said.

The opposition has been contacted for comment on the review.

The Greens defence spokesperson, David Shoebridge, who is a critic of Aukus, said the review would not change the fact that the ASA would not be acquiring any submarines in the near future.

“It’s a pretty extraordinary admission of failure when an agency that is less than a year-and-a-half old already needs a top-down external review,” Shoebridge told Guardian Australia.

“Aukus and the ASA are great at producing reviews, white papers, critical pathways and inter-agency taskforces. They just don’t seem to be able to produce any nuclear submarines.”