Police are asking for the public’s help after vandals sprayed a substance on the walls and steps of the Anzac Memorial in Sydney’s Hyde Park.

CCTV footage released on Friday shows two “unknown men” walking around the memorial around 12.20pm (AEST) on Thursday.

One man appears to spray a substance onto the eastern walls and northern steps of the memorial, while the other sprays a substance onto its southern steps. Shortly after, they both leave and walk together in a northern direction through Hyde Park.

The incident is being investigated by Sydney City Police Area Command, which has released images and CCTV vision of two men – both of Caucasian appearance and aged about 50 to 60 – whom they say might be able to “assist with inquiries”.

Chief Inspector Gary Coffey told a media conference the memorial was a sacred site for the community, representing a “significant sacrifice of life” during World War 1.

The stains from the vandalism are still visible, with the clean-up potentially costing up to $20,000.

“It’s absolutely disgusting, and that’s why we’re absolutely desperate for someone to identify these people,” Coffey said.

The first man is in the footage is described as being of a large build, with black and grey hair. He was wearing black sunglasses, a red and black check long-sleeve shirt with a blue striped shirt underneath, light coloured shorts, black boots with black socks, and carrying a red shopping bag cart.

The second man was of a solid build with a shaved head, wearing a dark-blue, button-up collared shirt, dark jeans and black sneakers with white trim. He was carrying a brown and black “man bag”.

The heritage-listed Anzac Memorial, designed by English sculptor George Rayner Hoff, was opened in 1934 as a tribute to members of the Australian Imperial Forces (as they were then known) who lost their lives as a result of World War I.

It has previously been the target of vandals, with large graffiti marks made on its walls earlier this year.

Anyone with information about the latest incident is urged to contact Crime Stoppers: 1800 333 000.