Werribee Open Range Zoo is celebrating its biggest year of visitation in its 25 year history, after attracting its 300,000th visitor this week.

The result for the 2008/09 financial year has beaten the previous best result by more than 15,000 visitors (last year's result).

Acting Zoo Director, Simon Finlay, said the achievement was a fantastic milestone, especially considering the decline in visitors around the bushfire period earlier this year.

"We think the result reflects the fact that people consider the Zoo as one of the best ‘value for money' leisure activities for a family to enjoy," he said.

"The difficult economic times has seen greater competition between leisure providers, and we believe people are choosing the Zoo over more expensive options because of the great value for a full day's entertainment."

Mr Finlay said the Zoo hoped to see more visitors through the gate for the upcoming school holiday period.

"We have a large range of school holiday programs for students of all ages, and we are about to launch an amazing new indoor exhibit, Smugglers Beware," he said.

"This exciting new exhibit is a ‘limited time only' event which is a fun, educational and interactive experience that focuses on the widespread and destructive wildlife smuggling trade.

"Entry is included in the general price of admission and because it's indoors, you can enjoy the exhibit in any type of weather."

Smugglers Beware runs from June 27 until October 4. For more information on school holiday programs, visit http://www.zoo.org.au/Learning/Public_Programs/Holiday