Skincare company Lush says concerns about the lack of a "mixed" workforce would prevent it opening a store in Israel - but it operates stores in Saudi Arabia.

And this week the company, which has just opened a new store in Brent Cross, north-west London, defended its decision to promote a pro-Palestinian song on its website.

Customers have been challenging staff in the Lush store in Brent Cross, about the company's support for Oneworld's single "Freedom for Palestine". The head office has received 223 emails to date on the issue.

On the Lush website, under "Our Ethical Campaigns" it says: "The catastrophe facing the Palestinian people is one of the defining global justice issues of our time."

Hilary Jones, the company's ethics director, admitted that Lush had been approached by the charity War on Want about putting the single online, but said it had not donated to the cause.

She said: "It was an easy decision. We trade with the region and forge links on both sides of the community. We buy olive oil from a Jewish-Arab project.

"But we don't feel it's a safe environment to have a store. Would we want a shop where we couldn't have a mix? We have a multicultural attitude to everything we do; we want everyone in the country where we are trading to be on an equal footing as far as basic human rights go. Some of the team would have to come through checkpoints and be treated differently on their way to work – that would be our worry."

Simon Emmerson, a Jewish musician who produces the soundtracks for Lush stores, said: "We are taking sides, definitely. The money isn't going to support Hamas, it's an issue of human rights. We've had long and very heated discussions about this. If people feel let down, we have to argue our corner. Other companies see these ethical campaigns as a PR exercise."

The Zionist Federation said it urged supporters of Israel to write to the store, and StandWithUs UK said it was "deeply disturbed" and was encouraging a boycott of Lush products and a letter-writing campaign. The ZF's director of public affairs, Stefan Kerner, said: "Refusing to open a store in Israel, whilst having stores in Saudi Arabia, just proves how blatantly biased the company are - and how they are more concerned with bashing Israel than staying true to their own ethical standards."

The English Defence League's Jewish Division advertised a protest outside the store last Sunday on its Facebook page, but staff said no organised group had appeared.

A member of staff at the Brent Cross store, which has been open for three weeks, said: "We have been worried about some demonstrations, but we support people's right to demonstrate and we would not ask Brent Cross to move people on if they came to protest. We have had a lot of people come into the shop and talk to us about it: some have been angry."

English teacher Judi Granit said she would no longer buy from the company, despite often having products shipped to her home in Haifa. She said: "I am absolutely broken-hearted. I have relished and supported the wonderful products for years. I am 100 per cent for supporting human rights around the globe and ending suffering, however, I do not condone untruths and lies, even if the intentions are good.

"I invite them to visit Israel and see that there is no apartheid here and no religious segregation. Yet the song 'Freedom for Palestine'" says the opposite."