Adrian Delia was never part of Forza Nazzjonali, Partit Demokratiku Marlene Farrugia said in a scathing attacking after the political coalition was officially dissolved on Friday.
"Forza Nazzjonali is a mindset that is thriving and growing by the day, while DeliaPN is shrinking and haemorrhaging by the hour," Dr Farrugia said on Facebook.
"DeliaPN's executive, does not realise that Forza Nazzjonali is a mindset."
The Nationality Party executive on Friday unanimously approved a motion to officially dissolve the agreement which created Forza Nazzjonali.
The motion, moved by secretary general Clyde Puli and seconded by all members of the party’s administration, refers to the agreement that had been reached between the PN and PD through which they presented a common list of candidates for the general election.
But Dr Farrugia said Forza Nazzjonali is made up of PN and PD together, and it is not miscible with DeliaPN, for obvious reasons, and as explained well by Daphne Caruana Galizia.
The representatives elected in the last election need to unite and work together, if a strong credible Opposition is to preserve democracy in our country, and eventually form a government to replace Joseph Muscat's "corrupt regime".
"Forza Nazzjonali lives on. DeliaPN was never a part of it, but PN was and is.
I am legally PN. Politically PD. Historically Forza Nazzjonali. And I cannot be dissolved. Not by a DeliaPN executive anyway," she said.
Dr Farrugia, a former Labour MP, vocally campaigned against Muscat's government in the last election, and was elected together with her partner Godfrey Farrugia, also an ex-PL minister. She has refused to accept Dr Delia as the new PN leader.
In a statement on Friday, PD said it continued to welcome disillusioned political refugees who had been failed by the parties forming the status quo and who, like the PD and its MPs, did not recognise Dr Delia as the Opposition leader.
PN candidate and former radio presenter David Thake also weighed in on the debate, asking why the party had distanced itself from an anti-corruption movement.
Watch: Times Talk - PN coalition agreement no longer stands