Francis Atwoli has castigated Kenya Airways for firing 131 maintenance engineers who were on strike.
Atwoli on Thursday said the action by CEO Sebastian Mikosz was unconstitutional as workers have a right to participate in a strike.
On Wednesday, the Employment and Labour Relations Court ordered the airline to refrain from replacing the engineers it sacked last week.
This came after the workers filed a case through their lawyers Anne Babu & Co and Ongoya & Wambola Advocates, challenging their dismissal.
Atwoli, who is COTU secretary general, said Mikosz should be busy addressing the industrial dispute and other issues raised by the engineers and technicians instead of rushing to sack them.
"Mikosz should also be assuring customers and KCAA of the safety of the aircraft, considering over 30 per cent of its 600 workers in the technical department have downed their tools. The CEO neither consulted nor engaged the two unions in the sector while making the decision to illegally fire the employees," he said.
The staff members, who include base maintenance, line maintenance, technical workshops, cabin and in-flight entertainment, multi-crew cooperation and technical assistants want to be paid between Sh340,000 and Sh1.2 million.
Atwoli is expected to meet workers from Kenya Civil Aviation Authority, Kenya Airports Authority, Kenya Airways and others on Saturday.
He said cases have been reported of workers being victimised, especially in the technical and engineering departments.
"This victimisation and threats should stop immediately. The workers are exercising their right to strike as enshrined in Act 41(d) of the Constitution," he said.
Atwoli said the meeting will discuss matters including delays in negotiating a new Collective Bargaining Agreement and failure by KQ management to address grievances raised by workers.
The complaints concern terms and conditions of service and have been raised through unions before - engineers also went on strike in December 2016.
Though the airline has already advertised the positions of those dismissed, the Labour court has ordered the management to refrain them.
The court also suspended the airline's firing of 131 striking engineers, technicians and technical assistants but did not order their reinstatement.