The reduction, to a total of 475,408 visits in the financial year ending on June 30 this year, was shown in figures tabled at this week's Otago Museum Trust Board meeting.
Otago Museum chief executive Shimrath Paul said the changes partly reflected the end of the "honeymoon" period for the museum's tropical forest attraction and the economic downturn.
Early this year, the museum seemingly faced prospects of a much bigger drop in attendance, until museum staff investigated gremlins in the automatic counting system at the front door.
Figures released late last year stated attendance had dropped about 50% - to 132,649 visitors - during the first five months of the 2009-10 financial year.
A total of 270,732 visits had been made in the comparable period in the previous year.
At a board meeting late last year, board member Dr David Hutchinson queried the greatly reduced attendance numbers.
At that stage, Mr Paul said the museum was investigating anomalies in the counting system.
Exhibitions, planning and development director Clare Wilson said a mechanical fault had been found in the museum's previous automatic counting system.
The earlier counter had been replaced, a backup system was in place, and some manual counting had been done as a further check, Ms Wilson said.
Adjusted figures released this week showed a 29% drop, to 191,342 visitors, in the first five months, instead of the previously advised bigger fall.
Mr Paul told the latest board meeting the 475,408 annual attendance was a positive achievement.
He added this week that, on a per-capita regional population basis, an attendance of about 300,000 would still be the highest at any regional museum in New Zealand and Australia.
A total of 70,653 people attended the museum's Discovery World science centre, which includes the forest, during the 2009-2010 financial year, down 23% on 91,361 in the previous year, latest figures show.
