The government refused to declare vacant six Dewan Rakyat seats held by former Bersatu members because they are scared to lose in elections again, claimed Muhyiddin Yassin.

In his speech at a party convention this morning, the Bersatu president said the recent Sungai Bakap by-election was proof there was increasing support for Perikatan Nasional.

"Despite being in power, they (the governing party) are very weak now.

"I have never seen in the country's political history where a ruling party could suffer such a defeat in a by-election. It was odd to see how they could lose so badly when they were holding all the powers.

"This is why they are scared to declare vacant the six Parliament seats and one state seat held by former Bersatu members, even when it goes against the Federal Constitution.

"They could violate the Constitution that they fought for before this because they are scared of losing," said the former premier when delivering his speech at the launch of the special convention in Selayang, Selangor.

It was held as a session to elaborate and instil Bersatu idealism and principles in party members.

In his speech, Muhyiddin claimed that the rakyat had become sick of the government and thus started to shift their support towards PN.

This, he said, was evident in the Sungai Bakap by-election in Penang where PN successfully retained the seat with a bigger majority.