Footage shows an anti-cannabis campaigner confronting the Thai Deputy PM today on the last day of campaigning before the country's elections.

Businessman and whistleblower Chuwit Kamolvisit demanded that Prawit Wongsuwan give his stand on the controversial issues surrounding the drug, which was decriminalised last year.

He asked how will Prawit solve the cannabis problem if he became the PM. Prawit said that he acknowledged and supported cannabis for medical use, not free cannabis.

Chuwit later asked Prawit to follow through on the pledge and wished him good luck to become the next PM. Prawit later smiled and told him 'just vote for me'.

The Palang Pracharath Party lead by Deputy PM Prawit Wongsuwan held their rally in the Din Daeng district of Bangkok, Thailand.

Voters head to the polls on Sunday, May 14 but must wait several weeks before the 'official' result is known, with parties negotiating behind closed doors to arrange a new government.

The army, which has repeatedly seized power, is expected to retain control of the country.