The new rules introduce a "solidarity" principle in that EU countries will have to help out neighbours in the event of a serious crisis, to ensure households and essential social services have access to gas supplies.
Regional groups will jointly assess supply risks and develop agreements on preventative and emergency measures, the Commission said, while natural gas companies will have to notify the EU of long-term contracts that could affect the security of supply.
The agreement was prompted by gas crises in the EU in 2006 and 2009, the Commission said. After these crises the EU brought in the first security of gas supply regulation in 2010. This required countries to prepare and share plans for national measures for crisis prevention and mitigation, obliged companies to ensure gas supply to protected customers even in the event of supply disruption, and provided for the installation of bi-directional capacity or reverse flows of gas.
However, stress tests have shown that many countries are still vulnerable to supply disruptions, and that better coordination between member states is needed, the Commission said.
Gas accounts for around a quarter of the EU's energy demand, and around 65% of the EU's gas is imported. The main suppliers are Russia, Norway and Algeria.
The EU's current annual gas demand of around 400 billion cubic metres is projected to remain relatively stable in the coming years, the Commission said.