The European Union is threatening legal action against member states which have yet to incorporate rules on electronic waste into their own national laws.

Official letters have been sent to Estonia, Latvia and Lithuania warning the countries that they must ratify the Waste Electrical and Electronic Equipment (WEEE) directive into national law.

In a similar move, Belgium, Denmark, Finland, Lithuania, Malta and Sweden have also been pulled up for not adopting rules banning certain hazardous materials in electronic goods.

EU Environment Commissioner Stavros Dimas said in a statement: "When these appliances become waste there is the danger that hazardous substances can be released into the environment and pose a danger to human health.

"These two directives are designed to minimise that risk, but member states need to properly transpose them into national law as quickly as possible to ensure the safety of their citizens."

If countries fail to act on the warning letters the matter will eventually be taken up by the EU courts, which could impose fines.