Melbourne Zoo visitor numbers soar thanks to free entry

The opening of new exhibits has seen visitor numbers at Melbourne Zoo soar, with an estimated 9000 people flooding through the gates on Tuesday alone.

Melbourne Zoo Director Kevin Tanner said numbers were up at all Zoos Victoria sites, including Healesville Sanctuary and Werribee Open Range Zoo.

Free entry for children under 16 throughout school holidays and on weekends as well as a newly reopened lion enclosure caused numbers to boom.

Mr Tanner said the renovations had been embraced by both the wildlife and the public.

"It is both bigger for the lions and has better viewing for the public," he said.

The enclosure, dubbed Lion Gorge, accompanies a new exhibit for wild dogs and the critically endangered Philippine crocodile.

Zoo memberships have also reached 200,000, and in the past six months 600,000 visitors have come through its doors.

Mr Tanner said a greater awareness for conservation had also helped increase numbers, including a sustainable palm oil campaign, which aims to prevent deforestation.

Tens of thousands of people have signed up to take action to support certified sustainable palm oil products on Melbourne Zoo's website.