The cafe will reopen - also in time for Fathers' Day on Sunday - after being closed for three weeks for earthquake strengthening work.
The work on the Begonia House was scheduled as part of the City Council's earthquake resilience programme.
The Council's Project Manager, Bruce Moorman, says the Picnic Cafe has been a priority for his team.
"We know it's a popular place for Botanic Garden visitors to eat, drink, relax and take in the surroundings. We worked fast and efficiently and strengthening work was completed ahead of schedule. This allowed us to do some extras, including painting all the steel work in the cafe."
Strengthening work is continuing on the rest of Begonia House with the aim for it to be fully reopened in time for the visitor peak in summer.
This Saturday also marks the fifth anniversary of the cafe opening in 2007 and the 40th birthday of cafe owner Paul Lester.
"It certainly is a nice coincidence and gives me double the reason to celebrate," says Mr Lester.
"This Sunday is also Fathers' Day, so if you're looking for something to do, take dad for a walk through the Botanic Garden finished off with a special lunch at the Picnic Cafe."