More than half of principals and vice-principals balloted on industrial action in Northern Ireland have said they are prepared to go on strike.
The National Association of Head Teachers (NAHT) said their members have spoken 'loudly and with strength' after being place under intolerable strain over the past eight years.
The union represents leaders in about two-thirds of schools in Northern Ireland.
In September, members were balloted to indicate their support for a strike and/or industrial action short of a strike.
Almost all respondents (94.8%) said they were prepared to take action short of strike as well as over half (57.8%) who said they were prepared for strike.
"Members of NAHT(NI) are no longer prepared to continue to prop up an education system at the expense of their health and well-being. All we are asking for is the caring actions of caring employers," said NAHT(NI) President Geri Cameron.
"As you would expect, our members wish to avoid any negative impact upon students’ education or safety. Therefore, any action will be intended to cause as minimal disruption as possible whilst placing pressure on the Department and employing authorities to resolve this crisis as a matter of urgency."
The union has indicated that they will be communicating any further action required by members in the latter half of next week.