The opposition cannot win any election, including the two upcoming by-elections, as long as it remains fractured, said former prime minister Dr Mahathir Mohamad.

This is made even more obvious after the opposition's failure to cooperate in the Sarawak state election on May 7, he said.

"The opposition (parties) cannot win if they are fractured. Their strife with each other caused them to lose in the Sarawak state election.

"So, the opposition will forever lose, while BN will win," he told reporters in Alor Setar today, as reported by Berita Harian.

In the 11th Sarawak state polls, PKR retained all three of its seats while DAP garnered seven out of the 82 seats up for contest. Amanah and PAS both did not win any seats.

Meanwhile, both Amanah and PAS are vying for the Sungai Besar and Kuala Kangsar seats, which were vacated after its incumbent MPs Noriah Kasnon and Wan Mohammad Khairil Anuar Wan Ahmad were killed in a helicopter crash in Sarawak earlier this month.

The Election Commission has decided that both contests will run simultaneously, with polling day set on June 18.

The two by-elections are viewed as litmus tests for Prime Minister Najib Abdul Razak in view of the allegations against him.