The Hoyts cinema multiplex will be refurbished and more than 1000 powered recliner seats would be installed, he said.
Botany will have more than 200 retailers once the project is finished.
The centre opened in 2001 and the works will be carried out by AMP Capital Shopping Centre, the specialist retail division with more than A$10 billion in assets under management.
A statement from AMP said the centre would be enlarged to meet growth in the area: "The expansion follows the Auckland Council Unitary Plan's designation of Botany Town Centre as a metropolitan zoned hub. Several Special Housing Areas and future residential growth areas have been identified surrounding the centre and have been fast-tracked for development. The redevelopment will enable it to cater to the needs of the growing population within the community."
Kiwi Property is building big at its Sylvia Park, planning to bring a department store to level one and almost finished a new office block there.
Scentre Group this month released $790m plans for its Westfield Newmarket, bringing David Jones to that site
Read more: Inside the mega-mall, what's about to hit Newmarket
It also plans to expand Westfield St Lukes and Westfield Albany and further announcements are expected from Scentre on these plans.