Sydney's Rookwood Cemetery will tighten its security after vandals smashed more than 70 gravestones.

Police have also been asked to investigate whether the crime was politically motivated after the graves, all in the Serbian orthodox and Russian orthodox areas, were smashed or knocked over.

Rookwood Cemetery chief executive officer Ian McIntosh said it would cost tens of thousands of dollars to repair them.

"All we can do is just do some internal stuff and increase our security until hopefully, we can catch the people in the middle of the act," he said.

He said he was disgusted by the attack and would do what he could to help the families of those buried there.

"It really makes me feel sick inside to be honest, that people can do this kind of thing," he said.

"We'll work our best, and we'll do the best we can to fix it up and relieve the families concerned."

The graves were damaged just before Ukrainian president Petro Poroshenko arrived in Australia for a two-day visit.

Peter Shmige from the Australian Federation of Ukrainian Organisations said he believed the attack was politically motivated.

"There is someone out there who is trying to stir up issues between Ukrainians and Russians here in Australia," he said.

He said earlier this year the nearby Ukrainian Catholic Church was desecrated with graffiti and this incident was designed to provoke tensions between Ukrainians and Russians in Australia.

"This incident as well looks to be somehow provocative due to the fact that it coincides with the arrival of the Ukrainian president," Mr Shmige said.

"There is someone out there who is trying to stir up issues between Ukrainians and Russians here in Australia."

Police say vandalism is 'un-Australian'

Police have condemned the attack as a "senseless, mindless act of vandalism".

"People have laid their loved ones here to rest and this is what occurs," said Detective Inspector Paul Arnold, from Auburn police.

"It's particularly un-Australian and doesn't assist anybody to have this done. Families would be particularly distraught."

Detective Inspector Arnold said police and cemetery staff were reviewing CCTV vision at the cemetery to try to identify the culprits, but the images have not helped the inquiry. But he believed more than one person was involved.

"I'd suggest, and I've got no information to prove this, that it possibly may be more than one person. Seventy-six headstones will take quite a bit of time," he said.

Inspector Arnold, however, played down suggestions the vandalism was racially motivated.

"There's nothing to indicate that a specific group was targeted," he said.

"Not only was it the Russian Orthodox area, the Serbian area. A number of other areas were also targeted and areas adjacent to it.

"It was only a small number of two or three headstones. But they weren't in the Russian area or the Serbian area."