Trade union official Brendan Ogle has lodged a High Court appeal of a Labour Court ruling which was issued last month and found he had not been discriminated against by his employer Unite.
Mr Ogle had claimed that his duties had been downgraded after his return from cancer treatment, a claim denied by Unite.
In October last year Mr Ogle lost a case at the Workplace Relations Commission (WRC) after it found that changes to his role at Unite were not related to his status as a cancer survivor.
An appeal of that decision was heard by the Labour Court in July, with a ruling issued in October.
Mr Ogle said at the time that the rejection of his case was a very disappointing outcome.
It is understood, the High Court appeal of the Labour Court ruling was lodged on Friday and that it has been listed for mention next month.
Last month, Mr Ogle dropped High Court defamation proceedings against two senior figures in the Unite trade union.
In September 2023, he issued proceedings against the union's General Secretary Sharon Graham and its former chairman Tony Woodhouse.
Mr Ogle claimed he had been defamed in speeches made by the two union leaders, a claimed denied by Unite.
A Unite spokesperson said that Mr Ogle's complaint was "comprehensively rejected" by the WRC.
"The decision of the WRC was subsequently upheld by the Labour Court," the union said.
"Unite will of course review this latest appeal and defend the claim."
"We are confident that the High Court will again resolve this matter in the union’s favour," Unite said.
