The weekend includes a public fireworks display and an academic parade, the opening of the "150 Years of Daring to Be Wise" exhibition at the Otago Museum on the Friday night which will run until late November, a Convocation Ceremony, and a banquet in the Dunedin Town Hall.
The university's 150th project co-ordinator for the year Kerry Buchan said five separate reunions would be held over the course of the weekend.
"We are expecting upwards of 1000 people participating over the weekend," she said.
The weekend reunions would also include a special day of events held by the Faculty of Law, on Saturday June 1.
The public were "really welcome" to join university staff, students and alumni at the Convocation Ceremony, where honorary doctorates would be presented.
The 150th procession, including academics, alumni and their families, was running from the School of Dentistry to Dunedin Town Hall, starting at 1.30pm, before the ceremony began at 2.30pm.
In the evening, there would be a 10-minute professional fireworks display in the Octagon, and an anniversary dinner would be held afterwards in the town hall - which was already sold out, 400 people attending.
The ceremony was free and open to the public, but people wanting to go needed to obtain tickets from the university
visitors' centre.
Ms Buchan would not be drawn on the total cost of the weekend, but said the fireworks display alone would be "more than $1.50".
An interfaith church service would be held on Sunday morning, at Knox Church, about 10am, which Ms Buchan said would be a "wonderful occasion" - before alumni who had gone to colleges would return back there for reunion lunches.
On Sunday evening there would be a gala concert event in the Dunedin Town Hall to raise funds for Breast Cancer charity EXPINKT, featuring performances from a variety of musicians - including classical singers Anna Leese, Joel Amosa and Kawiti Waetford, Rebecca Ryan and James Adams.
Tickets were still available.
Festivities would continue on Monday, with the Cameron Shield rugby match being held between Knox College and Selwyn College at the University Oval at 2pm.
"Everyone's welcome to come along.
"There's something for everybody, and it's going to be a wonderful weekend of celebrations," Ms Buchan said.
More information about the weekend is expected to be released in the next few days, and details of individual events are available on the University of Otago website.