People travelling to certain European countries must now submit visa requests at least 10 days before departure.

This follows changes to an international treaty, which governs cross-border movement between 15 European states.

The changes were made necessary due to increased security measures.

But a spokesperson for the 15 European countries said the changes would not affect the allocation of visas.Travellers who will be affected are those heading for countries which are members of the Schengen Convention.

These are Austria, Belgium, Denmark, France, Finland, Germany, Greece, Iceland, Italy, Luxembourg, Holland, Norway, Portugal, Spain and Sweden.

The convention came into practical effect in May 1995 and promotes freedom of movement between the 15 countries.

It allows citizens of the 15 countries to cross internal borders which separate them without checks.

But it also allows foreign visa-holders with no territorial restrictions for one country to enter another without any border checks.

Until last month, anyone needing a visa to travel to one of the Schengen countries could obtain it two to three days before travel.

But the installation of a new computer system has now slowed down the process.