Prime Minister Najib Abdul Razak should not be blamed for 1MDB's weaknesses as he was not involved in the operation of the state-owned fund, said an Umno leader.

It is not fair for the critics to single out Najib, said Deputy Minister in the Prime Minister's Department Razali Ibrahim.

"Najib is involved in various (other) matters, including those related to Petronas," he said at the Parliament lobby today.