The Coalition of Mother and Baby Home Survivors has rejected Taoiseach Leo Varadkar's assertion that it is too early to consider free DNA tests for the victims of false birth registrations.

The group says thousands of adopted people around the world are able to find blood relatives - and even siblings - by uploading the results of a cheap do-it-yourself DNA test onto a number of international genetic data bases.

Genetic testing using human DNA is described by the Adoption Rights Alliance as the "only game in town" where tracking down blood relatives is concerned.

According to the Coalition of Mother and Baby Home Survivors, people such as the 126 who were illegally registered as the natural children of parents to whom they were handed over by St Patrick's Guild, should be helped access those banks immediately.

The Children's Rights Alliance says the task ahead for illegally adopted people trying to discover their true identity is extremely challenging.

The National Archives have told RTÉ News that, in 1996, the Department of Foreign Affairs stored in its vaults 1,118 passport application files relating to children who were listed for foreign adoptions.

Over two decades earlier, Peter Berry, Secretary of the Department of Justice, said the State could not truthfully reject an American newspaper report claiming that 50 US couples had bought Irish babies through an international adoption ring for between $600 and $2,000 per child.

The Archives say the Commission of Investigation into Mother and Baby Homes has been given full access to the passport files.

Meanwhile, a spokesperson for the Adoption Authority of Ireland has said that there has been a huge increase in the volume of calls to the agency since the revelations of the illegal adoption registrations.

The spokesperson said that staff were collating the calls and there have been a "mixture of different queries" from members of the public.

Yesterday, Taoiseach Leo Varadkar told the Dáil that there were potentially "hundreds of thousands" of further illegal adoption registration records in existence.

Additional reporting Ailbhe Conneely