However, the SDHB says it will treat anyone who is assessed as needing admission.
Figures released to the Otago Daily Times under the Official Information Act showed each of the SDHB's mental health wards were full at some stage during 2017.
The rehabilitation ward was the facility most in demand, being full for 295 nights.
The SDHB has two acute wards, and both were busy last year.
Ward one was full for 148 nights, while ward two was at capacity for almost two-thirds of the year, at 203 days.
The SDHB said ''information is not available'' on how often people were sent away from emergency psychiatric services due to beds not being available.
Corinda Taylor, of Life Matters Suicide Prevention Trust, said she was stunned no records appeared to be kept of how many patients were turned away.
Life Matters had several anecdotal reports of people who had been unable to get a bed in mental health wards.
Not tracking those patients reflected the stigma attached to mental health cases, Mrs Taylor said.
''If those people were having a heart attack, would they be turned away and told we don't have any beds?''
SDHB mental health general manager Louise Travers said any patient who presented requiring care would be treated.
''Decisions are made whether their care is most appropriately managed in an inpatient or community setting,'' she said.
''We are always managing the needs of a large number of clients to ensure they receive the right care and when someone is assessed as requiring admission, they are admitted. We will find ways of ensuring this can occur, even when our wards are busy.''
Access to mental health services was a major topic discussed when the Government's inquiry into mental health and addiction services held its Dunedin public meeting.
Of the other mental health wards, the intellectual disability ward was full for six nights, the forensic ward for 48 nights, the intensive care ward for 88 nights, and the older persons ward for 124 nights.
