In the wake of the abduction and assault of Kevin Lunney, gardaí - mainly unarmed officers - had carried out patrols near the homes of QIH directors.
However, this has since been increased to include members of the Armed Support Unit (ASU), who are now understood to have a 24/7 presence in and around the homes of the senior staff members.
"Armed officers in the Q7 jeeps are now a regular sight on an around-the-clock basis near the homes," a source said.
Similar preventative arrangements are understood to be in place in the North for QIH directors living there.
The Irish Independent revealed last week how five QIH directors were formally warned by gardaí and the PSNI of credible threats against them.
In the latest death threat issued over the weekend, a masked man read out a pre-prepared statement which also threatens anyone who removes posters that have appeared in Cavan against the QIH directors. These remained in place last night.
Sources have now said that directors have increased security measures at their homes following advice from both police forces.
This includes the installing of security alarms which initiate protocols similar to that of tiger kidnappings, according to a source familiar with the arrangements.
Tiger kidnappings normally target a bank official where they, or their family, are abducted before the official is forced to withdraw large sums of money from a financial institution.
However, given the serious risk to the lives of QIH directors, similar security alerts have been put in place at their properties to combat the major threat to them.
Panic buttons, alarms and other special security measures have also been introduced at the homes of Quinn Industrial Holdings (QIH) executives.
This week, Kevin Lunney returned to his desk for a short period of time in what has been described as a "major morale boost" for both Mr Lunney and staff at the company.
Gardaí issued directors with Garda Information Messages - also known as GIM forms - after receiving credible intelligence of serious threats against the directors.
Similar security advice was also issued by the PSNI to those directors living in the North.
Speaking on RTÉ's 'Drivetime' yesterday evening, Tony Lunney said that his brother Kevin is healing - but that the ordeal has been both mentally and physically tough.
Commenting of the most recent death threats, Tony Lunney said: "It's crazy, it doesn't make any sense whatsoever, it's like a bad dream but you have to take it seriously.
"There has been intimidation going on for years now and we always thought, maybe, possibly it would fizzle out or settle down but what happen Kevin, he was left for dead, you can't underestimate any threat."
The five directors of QIH - Kevin and Tony Lunney, John McCartin, Liam McCaffrey and Dara O'Reilly - have not yet met with the Garda Commissioner, but Tony Lunney said it is hoped that this may happen next week.
Garda Commissioner Drew Harris has said he does not accept that lawfulness has broken down in the Border regions following the latest threats against QIH employees.
Speaking after addressing the Cabinet sub-committee on security with Taoiseach Leo Varadkar, Mr Harris said he feels confident with the progress being made in relation to the recent acts of violence.
"No, I do not accept that the Border area is lawless," he said.
"I will point to broad relations we have with the police service in Northern Ireland and will reiterate the resources we have in the Border area.
"We are there to enforce the rule of law and are there to ensure that people can go about their business.
"Since 2017 there has been an increase of 119 members and since then we have located an armed support unit in Cavan and a further 45 members will also be assigned to the Border area in February."
The Garda Commissioner added that the intimidating posters that are currently being displayed in various areas around Co Cavan will be removed.