"This has been a huge body of work by staff and I congratulate them for the professional way they have contributed to the process," Mr Williams said.
Mayor Steve Chadwick said the reorganisation was called for by the public during last year's election campaign.
"People told us they wanted council working differently and said the organisation was inefficient. The executive has now been able to respond to this."
Mrs Chadwick said the changes would enable a better organisation and also contribute $3.5 million towards annual savings - but acknowledged there would also be an impact for the district.
"Some people who are working for the district now will not have a job once the dust settles and that is unfortunate for us all as that pain will be shared across our community," she said.
Effective from July 1 council "core services staff numbers will reduce from 388 full time equivalent (FTE) staff from 388 to 322, a reduction of 66 staff.
Also, 192 FTE staff will be transferred to new Council Controlled Organisations.
Some 217 staff have been confirmed or redeployed into roles in the core organisation while 119 have been displaced and will be able to apply for 100 contestable positions.
Mr Williams said there was no confirmed number of physical staff reductions at this stage "as this will vary due to the recruitment process".
At the same time Mr Williams announced the council would look to the establishment of separate business units to look after tourism, events and venues, the I Site and Castlecorp.
"The relative strengths and weaknesses of the Council Controlled Organisation (CCO) proposals have been well debated and a lot of feedback has been received," Mr Williams said.
"Most people see the bringing together of tourism, events and venues and the I Site as logical.
Likewise, others are excited by the future potential of the Rotorua Contracting proposal. Rotorua Contracting would replace the old Castlecorp.
The Council still has to make the final decision on the formation of the CCOs and public consultation is still required, Mr Williams said.
"Forming business units does not commit council to the development of CCOs. These units could stay in this form if the decision was made not to progress the CCO concept," Mr Williams said.
He said he expected the process to be complete by November this year.