More than 70,000 vessels passed through the Malacca Strait last year traveling from Europe and the Middle East to East Asia, a sharp increase from about 44,000 in 1999, said Malaysian Deputy Prime Minister Najib Razak.
The narrow waterway is shared by Malaysia, Indonesia and Singapore and is used by vessels carrying half the world's oil and more than a third of its commerce.
"Malaysia believes there is an ultimate tipping point for maritime transit in the straits, beyond which further increases would become not only risky but also too dangerous and costly," Najib said while launching a Malaysian maritime research institute.
Najib said some researchers estimate that 120,000 vessels might use the Malacca Strait annually by 2015 if curbs are not introduced.
Malaysia will discuss the issue with Indonesia and Singapore, he said.
It was not immediately clear how any restrictions might be enforced.
Najib said security in the strait has improved significantly in recent years because of anti-piracy patrols conducted by the three neighboring countries. There have been no pirate attacks so far this year, compared to 75 in 2000, Najib said.