A group of young people have filmed themselves stealing wreaths and flowers that had been placed by schoolchildren at an Anzac memorial in Melbourne's east.

The Box Hill Memorial Gardens had been set up for Anzac Day commemorations.

The footage, shared on Snapchat early on Monday morning, shows two teenage boys running with armfuls of floral wreaths and placing them in front of two teenage girls.

The females are heard thanking them as they run back and forth bringing more wreaths. They laugh and swear throughout the video.

"The boys are picking us flowers," one of the girls says.

"Look how many he's got … he's got all of them. That's so sweet. I love you. Thanks babe."

The wreaths were trashed and left on the ground in the park. ( Supplied )

At one stage, one of the females is seen smiling as she holds one of wreaths on her head.

After the video was shared on Snapchat, it was then shared by another person on Facebook, who called their actions "putrid".

On Monday morning the memorial was found in disarray, with debris — including destroyed flowers and cards — scattered across the park.

The general manager at Box Hill RSL, Denis Fernando, said the incident was shocking.

"We're all disgusted and outraged. It's caught us off guard," he said.

"We actually thought a storm had come through, wreaths everywhere. Cards left by the schools were thrown around and some are missing."

He said only about 25 per cent of the wreaths were intact.

"The rest were destroyed. They would have gone into the bin," he said.

"It's just so disrespectful on the eve of Anzac Day."

The area has now been cleaned up but many of the flowers were destroyed. ( ABC News: Zalika Rizmal )

Council workers and RSL volunteers cleaned up the debris ahead of Wednesday's commemorations.

Sergeant Paul Basinski from Victoria Police confirmed officers were investigating the incident and had identified the people in the video.

A police spokesman said it was not clear whether a criminal offence had been committed.

The local mayor said the wreaths and flowers had been placed there by children at a service last Thursday.

Step back and think: Vietnam vet

About 1,100 local students attended.

"I'm personally disappointed that people have decided to act in the way they've done," Whitehorse mayor Andrew Davenport said.

"A lot of schoolchildren attended the school Anzac commemoration service and presented those wreaths, and to see the actions of a small group of individuals is disappointing."

Box Hill's Vietnam veterans group president, John Haward, said he could not believe what had happened.

"It's the significance of what they've done to desecrate the wreaths laid by schoolchildren," Mr Haward said.

He said young people should remember what the day stood for and respect the memory of those who served for Australia.

"Please respect the days around Anzac Day — it's one day of the year," Mr Haward said.

"Take a step back and think before you do things."