The man who was poised to become the interim president of the far-right National Front in France, will no longer take on the role after reports emerged he had questioned the existence of Nazi gas chambers.

Jean-François Jalkh was set to take over the party while Marine Le Pen focuses on her presidential campaign, National Front MEP Louis Aliot told BFMTV that Jalkh "thought there wasn't the calm necessary" for him to take on the top job.

Aliot added that Jalkh would "firmly and formally" contest the accusations of anti-Semitism made against him.

On Tuesday, La Croix journalist Laurent de Boissieu unearthed interviews from 2000 in which Jalkh seemed to deny gas chambers had existed during the Holocaust.

Jalkh reportedly said: "I consider that from a technical standpoint it is impossible — and I stress, impossible — to use it [Zyklon B] in mass exterminations. Why? Because you need several days to decontaminate a space ... where Zyklon B has been used."

Zyklon B was the Nazis chemical agent of choice during the Holocaust and was used in the Auschwitz-Birkenau concentration camp, among others.

Marine Le Pen is expected to return to the head of the party after she second round of the presidential vote takes place on the 7 May.

She faces the centrist candidate Emmanuel Macron who beat her in the first round on Sunday 23 April.