Allawah synagogue in southern Sydney vandalised with swastikas ...

A synagogue in southern Sydney has been vandalised with several swastikas spray-painted onto exterior walls in what NSW Police have described as "offensive" graffiti.

Police are investigating the incident at the Allawah synagogue and said it likely happened in the early hours of Friday morning.

Warning: This story contains an image of a Nazi symbol.

In red paint next to one of the swastikas was the message "HITLER ON TOP ALLAH…"

It follows a number of anti-Israel and anti-Semitic graffiti incidents in Sydney's east in recent weeks.

Last week, a car was spray-painted with the phrase "F*** the Jews" in Sydney's east at Queens Park, and last year a synagogue in Melbourne was the subject of an arson attack.

NSW Police said the latest incident was believed to have happened about 4:10am on Railway Parade in Allawah, with police from St George Area Command investigating the incident.

Police released CCTV footage on Friday which shows two people dressed in black hoodies approaching the building.

In a statement police said they would like to speak to a man who may be able to assist with their investigation.

"He is described as being of Mediterranean/Middle Eastern appearance, of medium build, and with a long brown beard," it said.

"The man was last seen wearing a black hooded jumper, black pants with a white stripe on the side, and aviator-style sunglasses."

Premier condemns 'monstrous act'

The Allawah synagogue is in NSW Premier Chris Minns's local electorate of Kogarah. 

Mr Minns labelled the vandalism a "monstrous act" and said it was carried out by individuals with "hate in their heart" determined to divide the community. 

"I think that the painting of a swastika on a Jewish building shows you everything you need to know about how appalling these particular individuals are and what their ultimate aim when it comes to members of the Jewish community," he said. 

"It's around the corner from my house, and I know that the people that I represent and the community that I live in completely repudiate that kind of horrifying vandalism, that horrifying violence in our community." 

Mr Minns said he had spoken to the president and vice-president of the synagogue, who were appalled by the incident.

"But they don't believe, and nor should they, that this is representative of the community's acceptance and closeness to the Jewish community in southern Sydney," he said.

NSW Police Assistant Commissioner Peter McKenna said he was confident those responsible would be caught. 

Police are investigating under Operation Taskforce Shelter alongside the counter-terrorism team. 

"Those people wanting to do this sort of thing we say to you, you will get caught, you will get prosecuted and you will be put before the courts," Commissioner McKenna said. 

Jewish leaders call for swift arrests

The President of the NSW Jewish Board of Deputies David Ossip said "enough is enough".

"It is not normal or acceptable that Australians are having to wake every morning filled with apprehension about whether or not there has been another anti-Semitic hate crime overnight," he said.

Sarah Schwartz, executive officer of the Jewish Council of Australia, said this wasn't only an attack on Jewish people but one on Australia's values of inclusivity and diversity. 

"Now, more than ever, we remain committed to fighting against all forms of racism in Australian society so individuals and communities can live without fear of discrimination or violence."

Alex Ryvchin from the Executive Council of Australian Jewry said the community expected those responsible to be arrested swiftly. 

"People who deface houses of worship with the symbol of genocide should face the full force of the law. As long as these people evade justice for trying to terrorise Australian citizens, it will continue," he said.

Mr Ossip noted that Nazi symbols and messages were illegal under Australian law.

"We cannot allow ourselves to become desensitised to acts of Jew-hatred and allow illegal conduct such as this to become normalised," he said.

"This behaviour is reprehensible and undermines the social harmony and cohesion which we all treasure."