The Northern Area Health Board is understood to be briefing its lawyers following the alleged intimidation of staff at a house for psychiatric patients near Swords, Co Dublin.
Gardai were again called to the premises yesterday to disperse protesters.
The board has confirmed that the first two of six residents of the St Ita's Hospital psychiatric service were relocated to the community home in Lispopple yesterday.
A spokesman for those opposing the health board's plan denied there had been any intimidation of contract workers or health board staff. They also deny any involvement in £30,000 worth of vandalism at Carlton House, which has been repaired by the health board.
No one has been charged in connection with the vandalism earlier this year.
Residents of the quiet Lispopple area stepped up their 12week protest early this week and the home has been placed under 24-hour guard by a private security firm employed by the board.
The Garda was called to the scene to disperse protesters early yesterday as senior health board staff and nurses arrived at the house with the two new residents.
It is understood the protesters have been informed they risk arrest for public order offences if their action goes beyond "peaceful protest". Garda sources said staff were "genuinely in fear" for their safety. The protesters deny they have intimidated anyone.
Some of those involved in the protest say they fear for their safety and they do not accept the assurances of the health board that the six mentally ill people will not pose a risk to the community. "We are worried about the presence of people with schizophrenic and psychiatric conditions in the area," said a spokesman for Lispopple residents.
The board and senior consultants in the St Ita's psychiatric service insist that the six patients have been rigorously assessed for their suitability to live in a community environment and that none has a history of violence or inappropriate sexual behaviour.
A residents' spokesman said there was an apparent conflict between the Department of Health and Children and the health board on the question of whether the board is responsible for the conduct of the residents outside the community house.
Referring to a recent reply to a Dail question on Department of Health policy in relation to clients of the psychiatric services, the spokesman said it had been made clear by the Minister, Mr Martin, that patients were "responsible for their own behaviour outside the property of the relevant health board".
The health board, however, repeated yesterday that it was responsible for the conduct of the residents both inside and outside the house in Swords.
A spokeswoman for the Department of Health and Children said there was no conflict between the two positions.
The health board was obliged to ensure "appropriate networks of care" were put in place for the patients but those living at Carlton House would have to have the "same responsibility as other citizens" for their behaviour.
Security staff and health board staff at Carlton House yesterday were reluctant to speak to the media. Blinds were drawn in a number of windows in the bungalow.
Two gardai remained in a marked vehicle inside the grounds of the house.