The posters of the Barisan Nasional (BN) candidate Datuk Mah Siew Keong in the Teluk Intan parliamentary by-election have been smeared with black paint again, besides the word 'stupid' written on them.

Mah said it was the second time the his posters were spattered with black paint, and he was notified via text messages by the public that most of them occured in Jalan Sungai Nibong.

Deploring the vandalism, he said the opposition should strive for a clean and fair campaign, instead of resorting to unbecoming actions.

"This has never happened before in Teluk Intan as it is against our culture," he told reporters after witnessing the early voting process at the Hilir Perak Police District Headquarters community hall here today.

Teluk Intan has 410 early voters out of 60,349 registered electors.

Mah, who faces DAP's Dyana Sofya Mohd Daud in the by-election, said he had restrained BN supporters from retaliating.

He described the smearing of his posters as a provocation intended to disrupt a fair and peaceful by-election scheduled for Saturday.

On criticisms against his manifesto, he said it outlined what he had done as a two-term Teluk Intan MP and a BN leader from 1999 and 2008 and what he aspired to do if he were elected again.

"The opposition should tell the people what they can do," he added.