Environment minister Lord Henley said: "Sales of 'green' goods contribute billions of pounds towards the economy while helping to reduce our impact on the environment.
"If people are making the effort to buy green, it is only right that we try to make the process as easy as possible."
Marks & Spencer and The Co-operative have welcomed the guidance. The Co-operative's annual Ethical Consumerism Report shows spending on green products in Britain increased from £1.4bn in 1999 to £7bn in 2009.
- The full report is available to read via the Defra website at www2.defra.gov.uk