But she said the organisation was trying to address cases more quickly and in a stronger way.
"With regard to changes in the number of cases going before the tribunal - there are a number of factors at play here," she said.
"It's fair to say that the nature of complaints has changed and required greater emphasis on transparency and public accountability.
Chief executive Terry McLaughlin said the number of complaints had been relatively consistent over the last few years but some of the disciplinary issues were a sign of the times.
Some members had got themselves into financial strife resulting in bankruptcy.
Any member who was convicted of a criminal offence would automatically face disciplinary action, McLaughlin said.
There had also been some people facing conduct issues over fee complaints.
A small minority of cases were also accountants who the body took action against because their work was not up to scratch.
McLaughlin said its disciplinary tribunal was run independently from the chief executive and management.
"I think the public can take confidence that we take this responsibility very seriously."
He said the public needed to be wary of accountants who were not members of the institute because there was no professional body for them to complain to.
The institute has 33,000 members.