The chair of the royal commission into the state’s mental health system has described as "totally unacceptable" the very high rate of suicide for lesbian, gay, bisexual, transgender and intersex Victorians.

LGBTI people have the highest rate of suicidality - which includes suicidal thoughts, plans and attempts - among any population in Australia, but the number of deaths is likely to be even greater because data on sexuality or gender identity is not consistently captured, the commission heard on Wednesday.

Ro Allen, LGBTI Commissioner at the Royal Commission into Mental Health. Credit:Justin McManus

Chairperson Penny Armytage told the commission that she was challenged by the suicide rate for members of this community and "trying to think how we respond better ... that’s totally unacceptable and it’s part of our terms of reference around suicide prevention".

Current figures show that LGBTI young people between the ages of 16 and 27 are five times more likely to attempt suicide, transgender people over 18 are nearly 11 times more likely and people with an intersex variation over 16 are nearly six times more likely.