The Garda or a Government- appointed commissioner should investigate Wicklow County Council's loss of a key file containing information on the illegal dumping of hospital waste in the county, according to the Labour Party spokeswoman on health, Ms Liz McManus.
Ms McManus, a Wicklow TD, is a member of the county council.
She joined Green Party councillor Ms Deirdre de Búrca in questioning whether the council was still an appropriate body to carry out an investigation into illegal dumping in the county.
Making her call for the Garda or a commissioner to investigate the loss of the file, Ms McManus pointed out that both the Garda and the council were currently carrying out separate investigations into illegal dumping in west Wicklow.
The missing file relates to the operation of a dump at Whitestown and is understood to include information, compiled by locals and submitted to the council, which may identify the owners and operators of lorries used in illegal dumping.
It is significant because it dates from 1998. A later council survey reported no evidence of serious illegal dumping at Whitestown.
Ms McManus told The Irish Times the file had been missing at least since a Garda request for sight of it last March.
The absence of the documents may hamper a prosecution against those identified.
Calling for the Garda to investigate the circumstances surrounding the missing file, Ms McManus said: "Here we have Wicklow County Council investigating the dumping and its own role in that, and now its own file had gone missing. Whatever is here has to be faced."
Ms de Búrca also questioned the council's continuing role as investigator, claiming the disappearance of the file had hampered the Garda investigation.
Meanwhile, county councillors from Wexford began a three-day tour of waste management facilities in Denmark yesterday, in advance of a vote next week on incineration.
The 18-strong group will view an incinerator, a restored landfill, a civic amenity site and a waste transfer station before returning home tomorrow. About eight councillors, as well as senior officials and members of the council's strategic policy committee on the environment, are taking part in the tour.
Councillors will vote on Monday on whether to accept a controversial waste management plan for the south-east that includes incineration. It previously rejected a similar plan by 19 votes to one.
This week's trip is the second undertaken by councillors in Wexford of incineration facilities in Europe. The previous tour, of plants in Denmark, France and Germany, took place in February 2000.
The usefulness of the trips has been questioned by a group campaigning against the introduction of incineration in the south-east.
The New Ross-based Research and Information Group said such tours were essential, but councillors were not given the means to ensure the information they obtained was independent.
"Visiting an incinerator is comparable to visiting Sellafield. In the absence of independent technical expertise and access to records, such visits are of limited value," it said in a statement.
This was borne out by the fact that an incinerator visited by councillors in Germany in February 2000, which had been described in favourable terms, had since been permanently closed by the German authorities for breaching emission limits.
Wexford County Council said the tour to Denmark was organised following the council's June meeting, at which a decision on the waste management plan was deferred.
Council members had requested further information following the meeting, including "first-hand inspection of a modern thermal treatment plant".
The council is the only local authority in the south-east still to take a decision on the plan, which was adopted in recent weeks by Kilkenny, Carlow and South Tipperary county councils, as well as Waterford City Council.
County councillors in Waterford voted to reject the plan, but that decision can be overturned by the county manager, Mr Donal Connolly. No site for the proposed incinerator has yet been identified.