"The inquiry will look into how the Havelock North water supply became contaminated, how this was subsequently addressed and how local and central government agencies responded to the public health threat that occurred as a result of the contamination," he said.
The terms of reference were very wide, and included any lessons and improvements which could be made in the management of the Havelock North water supply network and across New Zealand.
Cabinet would consider over the coming weeks who would lead the Government inquiry.
It will be undertaken under the Inquiries Act 2013. This will ensure it follows a clear statutory process and will have a range of powers such as the ability to call witnesses.
Last week Hastings mayor Lawrence Yule welcomed the government-intitiated inquiry.
"I welcome a completely high-level review of everything from the health impacts, the health response, the role of the district council, how this happened, the communications regime - it'll be a very widespread and detailed review," he said.
Initially the district council was going to look into the outbreak jointly with the Government, however, this had changed due to the scale of the event and the number affected.