Candie Gardens is set to be locked at night to protect an upcoming exhibition, the States has announced.
The Renoir exhibition will take place from September through to December, displaying works by 19th Century French artist Pierre-Auguste Renoir.
The States said it was working alongside the police to "implement some changes to the security of the museum".
It said the gardens would be locked "in the near future" to "ensure the site is secure".
The police dog section will be exercising its dogs later in the evenings, once the gates are locked. A sign has been put up to make the public aware, the States said.
Tickets for the exhibition remain available to book in one-hour slots.