The European Union agreed today to offer the Irish government legal guarantees on national sovereignty to help secure voters' backing for the EU's Lisbon reform treaty, EU diplomats said.

The guarantees, to be rubber-stamped by EU leaders meeting in Brussels, are intended to assure Irish voters who rejected the treaty in a referendum last year that Ireland's policy on matters ranging from military neutrality to abortion will be untouched by the treaty.

Dublin is expected to hold a new referendum by early October on the treaty, which would reform decision making in the EU and requires the backing of all member states to take effect.