In a rare jab at member states, the Commission will issue warning letters on Wednesday demanding action within two months.
This concerns 15 different EU directives that have recently come into force, but have not yet been fully implemented by all countries.
Sweden is being warned in six areas, including labour immigration from countries outside the EU, environmental crimes and the transport of dangerous goods.
If member states do not follow the rules they themselves helped decide, they ultimately risk being brought before the EU Court of Justice.
