UMNO member who becomes a candidate, proposer or seconder of an opposition party will be sacked, said party UMNO secretary-general Datuk Seri Tengku Adnan Tengku Mansor.

He said the matter was already enshrined in the party constitution and firm action would be taken against any party member who opposed UMNO.

Tengku Adnan said this when asked to comment on the action of UMNO Youth member Syed Rosli Syed Harman Jamalullail's announcement on social media that he would be contesting as an independent candidate at the Kuala Kangsar by-election because he was disappointed with Barisan Nasional's (BN) selection of candidate.

Syed Rosli is also the Taman Cempaka UMNO branch Youth assistant secretary.

"If it is true he will be contesting, he will be sacked... Let's just wait for the June 5 (nomination date)," he told reporters after handing out Ramadhan contributions to 52 surau and a briefing for tithe recipients, here, Tuesday night.

BN named Datin Mastura Mohd Yazid, the widow of Kuala Kangsar Member of Parliament Datuk Wan Mohammad Khair-il Anuar Wan Ahmad, as the BN candidate for the by-election.

The Kuala Kangsar by-election was necessitated following the death of Wan Mohammad Khair-il in a helicopter crash in Sebuyau, Sarawak, on May 5.

The Election Commission fixed polling for the by-election as June 18 and nomination on June 5.

In the meantime, Tengku Adnan, who is also Federal Territories Minister, urged the public against wasting food during Ramadan which would begin next week.