Immigration officials revealed last night that they were concerned at a fresh surge in apparent marriages of convenience.
Sums of at least €2,000 are being paid to Eastern European women to take part and in some cases gardai have found payments of up to €10,000.
After a fall-off last year in the number of applications for residency here, based on marriage, the latest unpublished figures show a rise for the first half of this year.
Officials acknowledged that a "significant portion" were organised solely to secure residency rights.
Now the Government is planning to take tough action here as well as actively participating in an European-wide clampdown.
Analyses of the figures have repeatedly uncovered unusual patterns of marriages and these are particularly evident in the applications involving Pakistanis and partners from the Baltic states.
Statistics for the first six months of this year show there were 76 applications involving Pakistanis and Latvians, compared with 114 for all of last year.
In the suspected sham cases, the men have predominantly been Pakistanis marrying Latvian women.
Overall, the number of residency applications based on marriage to an EU citizen dropped from 1,939 in 2010 to 1,617 last year. But between January and June last the total has jumped again to 960, roughly equivalent to the 2010 level.
A senior immigration official told the Irish Independent last night that gardai had investigated a large number of sham marriages and had found no evidence or foundation for claims that Eastern European nationals involved were victims of trafficking.
One-third of the 1,617 applicants last year were to marry a Latvian or Lithuanian national.
Until 2008, Ireland operated a rule that granted EU treaty rights only to non-EU nationals who already lived in another member state.
This prevented widespread abuse of the residency rights, but it was struck down by the European Court of Justice.
Issue
Gardai subsequently blocked about 150 marriages they believed to be shams but the High Court in Dublin then ruled that they had no right of objection under the law.
The issue is now being raised regularly at EU Justice and Home Affairs meetings by Minister Alan Shatter and British Home Secretary Teresa May.
But proposed changes to tighten the rules have not yet received majority support.
Officers from the garda national immigration bureau are working closely with marriage registrars to identify shams, while the Departments of Justice and Social Protection are pursuing a range of other initiatives.
Draft proposals to seal off the loopholes in Irish legislation are already included in a new immigration residence and protection bill.
But Mr Shatter has now asked his officials to take a fresh look at the proposals to make them more effective.