The Public Advocate's office says the four guardians are struggling with workloads heavier than those of their counterparts in any Australia jurisdictions after they acted as guardian for more than 250 people in 2011-2012.

The four guardians act for people with dementia or who are unable to make decisions for themselves because of dementia, stroke, brain injuries or intellectual disabilities.

The advocate's office took over as legal guardian ''of last resort'' for 252 people last year, up from 147 in 2009, with about one third of those requiring ''intensive intervention'' of at least 10 contacts a month with their case worker.

But the advocate, Anita Phillips, says that she has just five guardianship workers, including one part-timer, among her 14-strong staff.

''Their caseloads are unsustainable, the stress and pressure of the human tragedy they face daily is relentless, yet they keep going because they really care about these vulnerable people whom sometimes even their families have abandoned,'' Ms Phillips wrote in her office's annual report.

''We have one staff member to cover all the mental health advocacy, and one for all the children and young people.

''We have effectively four guardians, each with caseloads of about 50 individuals.''

Ms Phillips believed that, within a generation, up to 6 per cent of the territory's population might not be able to make decisions for themselves because of dementia, intellectual disability or brain injury, and has advocated for strategic planning to deal with the expected wave of impairment.

The advocate, who has been calling for several years for more resources for her office, said it was falling behind in many other key functions because changing legislation imposed more work and an increasing number of individuals were coming to the office for help.

''There are many functions that we were unable to do because of resource constraints and budget bids falling on deaf ears,'' she wrote.

''We are struggling to meet the demands of the current domestic violence and protection orders legislation. Proposed changes will broaden the definitions of violence, which will impose even further expectations, and we will only be able to attend court hearings when a litigation guardian cannot be identified for a person with a legal disability, leaving many vulnerable people unsupported.

''The Mental Health Section has not been able to continue to monitor compliance and ensure policy changes have been implemented, is unable to conduct a thorough systemic project, or meet with and establish links with community agencies/key stakeholders.''

Ms Phillips called for more recognition of the work of her staff and said she was worried that the government and the community did not value their work.

''The ACT community should be applauding, supporting and rewarding these unsung heroes who undertake roles and functions that no one else will do,'' the advocate wrote.

''In reality, the reverse is true, with staff forced to operate under the additional pressure of ever-reducing resources and threats of losing rather than increasing their numbers.

''Sadly, I suspect that the lack of community and government support possibly reflects the lack of value placed on the remarkable work they do.''