Museum chief executive Shimrath Paul said yesterday's 20th anniversary of the centre was a "wonderful occasion".
It had been "very heartening" to have reached so many visitors, mainly from Otago, over the years, and "greatly satisfying" to have influenced their understanding and appreciation of science, Mr Paul said.
Key factors in the centre's success had been its focus on meeting community needs, and tight financial management, he said.
Whereas some other science centres elsewhere in the country had initially spent heavily on buildings or costly exhibits, and many no longer existed, the Otago centre had mostly been run on a shoestring, organisers said.
The Otago centre initially occupied relatively small ground floor premises, having gained its first electronic exhibits quite cheaply by auction.
It doubled in size to about 600sq m when it moved up to the museum's first floor in 1996, and with the advent of the Tropical Forest in 2007, now occupies about 1000sq m.
A $2 million grant which the museum gained from the Lottery Grants Board science subcommittee in 1992, to expand the centre, proved a catalyst, strongly contributing to the overall $6 million first stage of the museum's redevelopment.
Crowds attracted to the tropical forest since 2007 have also contributed to the growing popularity of the overall museum, organisers said.
Biggest attraction
• Tropical Forest, incorporating a tropical butterfly house, with more than 400,000 visits since 2007.
• Butterflies Alive show attracted 15,000 visitors (December 1994-February 1995).
