Vandals have desecrated a Ukrainian church in Sydney's west, spraying swastikas and hate messages on the outside wall.

When the priest at St Andrew's Catholic Church in Lidcombe woke on Saturday morning, he discovered the back wall of the church had been covered in graffiti.

The graffiti includes swastikas and Ukrainian writing that reads "burn in hell fascists".

Pete Shmigel from the Australian Federation of Ukrainian Organisations says it is an unacceptable hate message.

"[It is] swill that's been condemned by the United Nations, by our own Government, by United States and Canada as simply false and untrue," he said.

"Ukrainians are aiming for democracy, they reject fascism in every way."

He says the messages echo the "propaganda that's been coming from [Russian president] Vladimir Putin to justify invading Ukraine".

"In some respects we're not surprised - in the same way that Vladimir Putin has exported violence to Ukraine, somebody who supports Vladimir Putin is now exporting violence to Sydney," Mr Shmigel said.

He says police have been informed, and on Sunday parishioners will gather to pray for those responsible.

"There's something wrong with someone who does something like this and they need our help and prayer," he said.

"But they also need to be fully investigated by the New South Wales police in terms of what other hate crimes they might be capable of."