This section prohibits, subject to its provisions, agreements between undertakings, decisions by associations of undertakings and concerted practices whose object or effect is to prevent, restrict or distort competition in trade in goods or services in the State or any part thereof. Examples include fixing prices or trading conditions; limiting or controlling production, markets, technical development or investment; sharing markets or sources of supply; applying dissimilar conditions; tying contracts to unrelated obligations; and bid‑rigging. "Bid‑rigging" is defined to include agreements not to submit or to withdraw bids, submission of bids on agreed terms and collusive tendering; a "relevant bidding process" is a process requesting bids or tenders to supply goods or services, to produce a product or to enter a concession contract.

An agreement, decision or concerted practice is not prohibited if it meets the conditions in subsection (5) or falls within a category declared by the competent authority with the concurrence of the other competent authority; declarations must be published and may be revoked with concurrence. The conditions require that the arrangement, having regard to market conditions, improves production or distribution or promotes technical or economic progress while allowing consumers a fair share of the benefit and does not impose terms not indispensable to those objectives or enable elimination of competition in a substantial part of the products or services. Courts may sever prohibited terms and order recovery or restitution; implementation of mergers or acquisitions in accordance with Part 3, together with directly related and necessary restrictions notified under section 18, is not prohibited. References to parties include one or more parties and subsection (9) is without prejudice to section 11(a) of the Interpretation Act 1937.