Plans are afoot to introduce a barcode identifier on each envelope to 'name and shame' any TD or senator whose envelopes turn up in the hands of 'associates' using them for electioneering purposes.

Under existing legislation, TDs could lose their allowance, worth over Euro10,000 a year for each of the 226 TDs and senators, if they allow "another person" to use their pre-paid envelopes for anything other than parliamentary duties.

But despite the ban, numerous councillors and 'party friends' were found to be using mysteriously-acquired Oireachtas envelopes for their own electioneering.

Over two years ago, Fianna Fáil councillor Lorcan Allen prompted outrage among the party faithful when he used 2,000 pre-paid Oireachtas envelopes to distribute a bogus letter 'signed' by Taoiseach Bertie Ahern urging people to vote for the councillor.

Though Allen was kicked out of the party for a year, a thorough investigation by Fianna Fáil head office failed to reveal the identity of the TD who gave Allen the envelopes.

The Allen affair - and other abuses by TDs, such as using their envelopes to send Christmas cards - finally prompted the Dáil Committee on Procedures and Privileges to crack down on the abuse.

The barcoded envelopes will be in use by May this year, which may be in time for the election, according to a spokeswoman for the Oireachtas commission which runs the Dáil and Seanad. But Fine Gael senator Paddy Burke doubts the system will be effective.

"It is no secret that senators swap their envelopes. If a senator has run short in one month, they will borrow from another senator who may have a surplus. If some of these envelopes end up used for electioneering purposes, the barcode identifier may finger the wrong TD or senator, " he said.

But Burke admitted that Oireachtas envelopes are in demand at election time. "At election time it's more a question of swiping than swapping.

Any politician will find it hard to walk past an envelope during an election, " he said.