The "reasoned opinions" have been issued six months after the countries were supposed to have fully implemented the new laws. The reforms gave individuals several new rights, including the right to better information about how internet service providers manage access to their networks and set out a requirement for website owners to obtain consent from users in order to track their online behaviour.

Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, France, Germany, Greece, Hungary, Italy, The Netherlands, Poland, Portugal, Romania, Slovenia and Spain have still to fully implement all of the reforms, the Commission said.

The Commission can take legal action against countries that do not correctly transpose EU law or fail to notify that they have passed national measures to implement EU rules.

The Commission previously issued 20 EU member states with letters of formal notice regarding the reforms in July. The letters are the first legal stage open to the Commission when it identifies infringements from countries that have not enacted EU laws. The letters required member states to detail their views on any infringements they may have made.

Latvia, Lithuania, Luxembourg, and Slovakia have subsequently fully implemented the EU reforms into national law, but the remaining 16 countries have still to do so, the Commission said. In the second stage of its infringement proceedings the Commission has now issued "reasoned opinions" to each of the 16 states. The opinions formally request that countries comply with EU law within a set timescale, usually two months.

Countries that do not comply with the requirements of EU law can be referred to the European courts. The European Court of Justice can order EU member countries to implement EU Directives and fine them if they do not.