Former MCA president Dr Ling Liong Sik has applied to strike out Prime Minister Najib Abdul Razak's defamation suit.

Former prime minister Dr Mahathir Mohamad has also filed an affidavit in support of the application.

Parties to the suit have informed Kuala Lumpur High Court judge John Louis O'Hara, who fixed March 31 for further case management for Najib's lawyers to seek instructions.