Target is suing a San Diego gay rights group for canvassing outside its stores.

The US retail giant claims that Canvass For A Cause, which is working for gay marriage, is driving away its customers.

Target has already been criticised for donating money to anti-gay political groups. Lady Gaga recently walked away from an exclusive Target deal over the issue.

Last year, the retailer gave a $150,000 donation to Minnesota Forward, which used the funds to back Republican state gubernatorial candidate Tom Emmer, who is against gay marriage and has voted against other gay rights initiatives.

The retailer’s case against Canvass For A Cause begins today.

Target says that the gay group’s activists regularly canvass outside eight San Diego stores and refuse to leave when asked. The retailer says it receives around a dozen complaints every day from shoppers angry at the campaigners.

But Canvass For A Cause, which asks people to sign gay marriage petitions, claim Target wants to silence it because it is against gay rights.

Director Tres Watson told AP: “It’s very David vs Goliath. We understand they’re the Goliath in the room. They’ve got all money in world to get us to stop talking about gay marriage.”

He added that volunteers are trained to be polite and professional and that shopping centres have been recognised as public places where freedom of speech is protected.

After the donation to Minnesota candidate Mr Emmer, Target said it would “use the benefit of time to make thoughtful, careful decisions on how best to move forward”.

It received a 100 per cent rating in the Human Rights Campaign’s annual diversity index before the controversy.

Responding to Lady Gaga’s public criticism, it said: “Target remains committed to the LGBT community as demonstrated by our contributions to various LGBT organisations, our recently established Policy Committee to review our political giving and our respectful, inclusive workplace environment.”

Target voluntarily pays benefits to same sex partners, despite no federal requirements to do so.