Mr Oram told the Rotorua Daily Post one of the major reasons he wanted to attend was to learn about what Rotorua had done to improve water quality in the Te Arawa lakes.
"If we want to have healthy ecosystems, we have to have healthy aquatic ecosystems."
Individuals and businesses needed to help protect and improve the environment, he said.
"Each of us in our own lives needs to take far more responsibility."
Mr Oram said sustainability was not just up to the Government and councils.
"Part of the solution is about how businesses respond.
"To me, this is absolutely mainstream business to think about deep sustainability.
"The Government can regulate, but then it's up to businesses of all kinds who need to play their role, but so do the people."
Mr Oram said he hoped to bring to the forum knowledge about water quality around the rest of the country, and in an international context.
There were 85 people already registered to attend by Monday, but there were still spaces left.
"There's still plenty of room for others who want to come," Ms Chadwick said.
Attendees were encouraged to register in advance, although it would still be possible on the day.
The symposium, organised by the Lakes Water Quality Society, runs tomorrow and Friday and focuses on the issues of pest fish, lakeweed and water quality.
Entry to the forum is free for students, and $20 for others.
Mayoral Environmental Forum
What: Discussion of sustainability issues, Q and A session
Who: Mayor Steve Chadwick, Rod Oram and Sir Rob Fenwick
Where: Mokoia Room, Millennium Hotel
When: Thursday 5.30pm-6.30pm
To register or buy tickets, go to https://symposium-mayoral-forum.lilregie.com/step1
