The Japanese company behind humanoid robot Pepper has told its owners not to get frisky with it. In the user agreement for the android, mobile phone firm SoftBank states: "The policy owner must not perform any sexual act or other indecent behaviour" on the machine, which is designed to live with humans.

Pepper was produced in collaboration with French robotics company Aldebaran SA and went on sale in June for $1,640 (£1,078). The so-called "social companion" is already greeting and interacting with customers in SoftBank's 74 stores in Japan. Nestle also employs Pepper to sell its coffee machines in the country. Touted as the world's first personal robot with its own "emotions", Pepper is so popular that 1,000 units produced for September sold out within a minute, according to a statement issued by SoftBank. The next batch is set to go on sale on 31 October.

Aldebaran says: "Pepper is much more than a robot, he's a companion able to communicate with you through the most intuitive interface we know: voice, touch and emotions." The user agreement also forbids using the four-foot humanoid to send spam or cause harm to other people. SoftBank has said that perpetrators of sexual acts with Pepper could face punitive action, but did not specify the consequences or how anyone would find out.

Earlier in September the "Campaign Against Sex Robots" was launched, calling for a ban on the development of machines that can be used for lewd acts. "Sex robots seem to be a growing focus in the robotics industry and the models that they draw on – how they will look, what roles they would play – are very disturbing indeed," Dr Kathleen Richardson, a robot ethicist at De Montfort University, told the BBC.

"We think that the creation of such robots will contribute to the detriment of relationships between men and women, adults and children, men and men and women and women," she said.

Also earlier in September, it was reported that Pepper was assaulted by Kiichi Ishikawa, a 60-year-old Japanese man unhappy at the level of service provided by the bot's human colleagues. Pepper was left nursing possible internal processor damage after the alcohol-fuelled episode, which resulted in Ishikawa's arrest.