The charity regulators for Northern Ireland and the Republic of Ireland will be included for the first time in the body that develops the Statements of Recommended Practice for the charity sector.
The Charity Commission for Northern Ireland and the Charities Regulatory Authority for the Republic of Ireland will join the Charity Commission and the Office of the Scottish Regulator on the Sorp-making body when it begins developing the new Sorp in January 2019.
The addition of the two Irish regulators has been approved by the Financial Reporting Council and is subject to the Sorp being formally adopted in the Republic of Ireland.
The new Sorp, which covers financial reporting, auditing practices and actuarial practices in the charity sector, will be the first to cover all four charity law jurisdictions in the British Isles.
The CCNI and the Irish regulator have been observer members of the Sorp Committee, which advises on the creation of the Sorp, since 2010.
Frances McCandless, chief executive of the CCNI, said: "This renewed partnership will allow us to work closely together to create a high-quality reporting and accounting framework for charities that can command the confidence of donors and funders across the UK and Ireland."
John Farrelly, chief executive of the Charities Regulatory Authority for the Republic of Ireland, said: "We welcome this step and are confident that this collaboration will result in an effective common reporting and accounting framework suitable for all four jurisdictions that also respects the unique reporting requirements for both Ireland and the UK."
Helen Stephenson, chief executive of the Charity Commission, said: "I hope that this will equip us all to help charities rise to the challenge of addressing public concern and explaining their impact through accurate and meaningful reporting."
David Robb, chief executive of the OSCR, said: "The charities Sorp has a long history and we look forward to working together to ensure high-quality, proportionate reporting and accounting, which is crucial in order for charities to demonstrate that they operate transparently and can be trusted in the eyes of the public."