Dress codes requiring employees to wear make up or have manicured nails is likely to be unlawful, the government has suggested in guidance to help employers understand the law and workers' rights better.

The Government Equalities Office, the Department for International Development and international development secretary Penny Mordaunt issued guidance, entitled Dress codes and sex discrimination: what you need to know, yesterday following recommendations made by the Commons women and equalities, and petitions select committees earlier this year.

The nine-page document states that dress codes can be a legitimate part of an employer's terms and conditions of service. However, employers are advised to avoid gender-specific rules. 'For example, any requirement to wear make-up, have manicured nails, wear hair in certain styles or to wear specific types of hosiery is likely to be unlawful, assuming there is no equivalent requirement for men,' the guidance says.

Listing examples, the guidance says requiring female employees to wear high heels but not having footwear requirements for men is likely to constitute direct discrimination. It could also amount to indirect discrimination against disabled employees as heels can exacerbate mobility difficulties or increase the risk of falling for those who are visually impaired.

However, requiring receptionists to dress smartly, to portray a positive public-facing image would be lawful because it is not a gender-specific requirement. Requiring all employees to wear smart shoes would also be lawful.

Beverley Sunderland, managing director at Abingdon firm Crossland Employment Solicitors, said the government has issued 'what can be best described as a "Janet and John" guide'. Phrases such as 'it is best to' and 'likely to be' reinforces the view that the law is not clear enough, she added.