Former prime minister Mahathir Mohamad faces a three-way contest in Langkawi against Barisan Nasional (BN) incumbent Nawawi Ahmad and local Parti Islam SeMalaysia chief Zubir Ahmad.

"We are confident," he told The Sunday Times of his prospects on the island he helped build. But Mr Zubir said: "Everyone has an equal chance and whoever can accelerate at the last minute will win."

Tun Dr Mahathir, 92, quit Umno, the dominant party in the ruling BN, over disagreements with PM Najib Razak, and now heads Pakatan Harapan (PH).

As PH's candidates are standing under Parti Keadilan Rakyat, Dr Mahathir's image cannot be used on posters outside Langkawi under new regulations.

That has not stopped the feisty orator from hitting out at what he sees as attempts to stymie PH.

Dr Mahathir claimed on Friday that the private jet he was to board for the island had been sabotaged. Just before take-off, the pilot said its tyres were damaged.

Yesterday, a sympathetic Deputy PM Ahmad Zahid Hamidi said: "I hope it was not done by certain parties to block him from contesting."

Civil Aviation Authority of Malaysia (CAAM) chairman Azharuddin A. Rahman said it had investigated the allegation and found no recent reported defect, except for air leakage from the left hand nose wheel. It could not be replaced as there were no spares.

"CAAM has found no indication whatsoever of any sabotage," he said, adding: "Allegations of sabotage against an aircraft are extremely serious, and could impact the reputation of Malaysian aviation and the country as a whole, especially in this sensitive general election period."

Dr Mahathir replied at a rally in Langkawi last night: "I consider that it was deliberately done because there was an intention to prevent me from nomination."