Councils must give notice of a meeting, provide an agenda and open the meeting up to everyone unless a formal resolution was passed to exclude the public, Boshier said.
"I am aware some councils may be incorrectly applying the law when making these formal resolutions.
"The public may become suspicious if councils repeatedly use closed workshops or informal meetings to discuss issues."
The investigation will focus on eight councils across the country - Rotorua Lakes Council, Taranaki Regional Council, Taupō District Council, Palmerston North City Council, Rangitikei District Council, Waimakariri District Council, Timaru District Council, and Clutha District Council.
"I have chosen these councils for a variety of reasons," Boshier said.
"Some councils are getting it right. I want to understand how they achieve this and share their good practices with other councils so we can all learn from this investigation."
Another point of concern was note-taking and record-keeping during these informal workshops, he said.
"The public are within their rights to make official information requests about what has been happening during these workshops so accurate accounts are a must. "
With the local elections looming, Boshier clarified this investigation was not focusing on individual elected representatives.
Feedback from the public, councils and their staff on council processes and experiences will be sought until August 26, 2022.
The councils will also be given a chance to comment on the Chief Ombudsman's provisional opinion before the final report, which is expected in mid-2023.