Newly released figures imply that the number of women arriving in Ireland in late pregnancy in order to claim citizenship for their child represents only a tiny proportion of total births.

The figures were released by the Minister for Justice, Mr McDowell, as a bitter Dáil debate got under way yesterday on the Government's proposal to hold a referendum to allow the Oireachtas restrict the existing automatic entitlement of children of non-nationals to hold Irish citizenship. The Dáil proceedings continue today.

The statistics and documents published yesterday indicate that there is a phenomenon of "citizenship tourism", as Mr McDowell has insisted, but that it appears to be very small.

In the Dáil yesterday Mr McDowell said he knew anecdotally of "women from eastern Europe and elsewhere in the world who have come here on holiday visas, given birth, collected the birth certificate and the passport for the child and returned home." The Government has said that the need to end this phenomenon is among the reasons for holding an early referendum.

However, the statistics show that in 2003, just 442 births in the two largest Dublin maternity hospitals were to non-EU nationals who either booked into the hospital late or arrived without booking at all.

Of these an unknown number involved births to non-EU nationals legally resident in Ireland, and a small number are believed to have involved women transferred from other hospitals because of medical complications.

Based on these figures, best estimates suggest that between the Rotunda and Holles Street hospitals there was roughly one birth a day to women arriving late in pregnancy - the category to which so-called "citizenship tourists" belong.

There are no statistics available of this type for the third major Dublin maternity hospital, the Coombe. There were 22,895 births in the three main Dublin maternity hospitals in 2003.

Another letter released yesterday from the Master of the Coombe Hospital, Dr Sean Daly, in January 2003 suggests that many of the pregnant women arriving at the last minute in Dublin hospitals to give birth are not coming directly from outside the State, but are asylum seekers already resident elsewhere in the State who choose to come to Dublin to give birth. If true this means the number of "citizenship tourists" is smaller.

Nevertheless an internal Department of Justice memo also released yesterday reports that in August 2003 the Masters of the maternity hospitals said there was "quite a number" of pregnant women who "arrive with their antenatal notes from the UK, deliver and return immediately. According to Dr Declan Keane, Master, Holles Street, this cohort is now causing the hospitals greater difficulty than the asylum seekers," this memo says.

Other letters and records released show that the Masters of Dublin's three main maternity hospitals have been expressing concern to the Government for 18 months about the growing number of non-national births. The letters from the Masters do not propose any constitutional change, despite the assertion last month by Mr McDowell that they had "pleaded" for constitutional change.

However, an internal Department of Justice memo of August 2003 reports that the Masters believed that "something needs to be done to tighten up controls in the immigration area".

A note of a meeting between the Minister and two of the Masters in October 2002 appears to bear out Mr McDowell's insistence that in proposing the referendum he is motivated by a desire not to fuel racism. He promised the Masters decisive action to ease the pressure on maternity services caused by the high number of asylum seekers arriving late in pregnancy, as the existing difficulties were "fuelling racist thinking" among the public, the note says.

The Taoiseach yesterday spoke strongly in support of holding the referendum on June 11th.