Vandals have targeted a Christchurch synagogue with anti-semitic graffiti apparently triggered by the Middle East conflict, but a New Zealand Jewish leader says it is uncertain what motivated the attack.

Slogans such as "Filthy Pigs" and "Shower you murderous swine" were scrawled in green paint under cover of darkness and were discovered on the pavement outside the fence yesterday morning.

The vandalism, condemned by the Jewish community, came after news reports of an Israeli air raid in Lebanon that killed at least 54 civilians including 37 children.

Members of Christchurch's Jewish congregation who were at the synagogue inspecting the graffiti yesterday did not want to be identified for fear of being targeted themselves. One said the vandals had probably been "stirred into activity" by scenes of Israel military strikes in Lebanon.

"People seem to rise to the occasion and come and do something like this. There are certainly lots of people with different opinions and a lot who are quite happy to blame Israel for what they see happening."

The chairman of the New Zealand Jewish Council, Geoff Levy, said the "vile acts" of graffiti were regrettable.

It was difficult to tell who was responsible and to be certain what the motivation was, as Israel was not mentioned.

"If it has links with Israel, it exists only in the mind of the perpetrators. This seems like simple vandalism - simple anti-semitic expression, and that sort of behaviour is to be deplored and is something that we are very upset has occurred."

Mr Levy said this was the first offensive act aimed at the Jewish community he was aware of since the conflict between Israel and Hizbollah escalated recently.

"Generally speaking, New Zealand is a pretty peaceful place. It is so much easier when Israel was the underdog. It is not seen as being the underdog at the moment. Quite often, many people in our society will favour those perceived to be the underdog."

The slogans were painted over yesterday afternoon. The congregation had still to decide whether to lay a complaint with the police, but Inspector Gary Knowles said he would be interested in hearing more.

On Sunday, a mosque in Lower Hutt was spray-painted with swastikas and the number 666.