Prime Minister Dr Mahathir Mohamad has complained that Malaysians listen to rumours from Singapore, but not to him.
He also implied the rumours were aimed at undermining Malaysia's economy to the advantage of Singapore.
The two countries have recently been arguing over traffic jams on the causeway linking Singapore and the southern Malaysian state of Johor, with each government blaming the other.
A rash of rumours circulating in Malaysia and Singapore during the past few days has questioned the health of Dr Mahathir and the Malaysian economy.
'From Singapore you get three rumours a day,' Dr Mahathir said.
'And Malaysians act in full faith on those rumours, but if the Malaysian Prime Minister told them the truth, they would say he is lying.' He said Malaysians did not start rumours about Singapore.