Zonal re-registration has been developed to facilitate the evaluation of the large number of product re-registration applications expected in the next few years in all Member States (MS). It is an initiative developed on a voluntary basis between competent authorities of MS in all three zones (Southern, Central and Northern) and is similar to the zonal authorisation procedure included in the new regulation to replace 91/414/EC.
http://www.pesticides.gov.uk/approvals.asp?id=2785