1. For the purposes of implementing this Directive, Member States shall, in accordance with national legislation and/ or practice, designate one or more liaison offices or one or more competent national bodies.

2. Member States shall make provision for cooperation between the competent authorities or bodies, including public authorities, which, in accordance with national law, are responsible for monitoring the terms and conditions of employment referred to in Article 3, including at Union level. Such cooperation shall in particular consist in replying to reasoned requests from those authorities or bodies for information on the transnational hiring-out of workers, and in tackling manifest abuses or possible cases of unlawful activities, such as transnational cases of undeclared work and bogus self-employment linked to the posting of workers. Where the competent authority or body in the Member State from which the worker is posted does not possess the information requested by the competent authority or body of the Member State to whose territory the worker is posted, it shall seek to obtain that information from other authorities or bodies in that Member State. In the event of persistent delays in the provision of such information to the Member State to whose territory the worker is posted, the Commission shall be informed and shall take appropriate measures.

The Commission and the public authorities referred to in the first subparagraph shall cooperate closely in order to examine any difficulties which might arise in the application of Article 3(10).

Mutual administrative assistance shall be provided free of charge.