Prime Minister Najib Abdul Razak's aide Tengku Sariffuddin Tengku Ahmad has challenged DAP leader Lim Kit Siang to "admit to his alleged ambition" of wanting to be deputy prime minister.

"Lim needs to come clean on this, as it is the right of Malaysians to know who they will be ruled by if they vote for Pakatan (Harapan).

"He must tell the people whether it is his political ambition to be the deputy prime minister, as confessed by Mahathir on Jan 19, 2017," said the press secretary in a statement today.