Kuala Lumpur - Malaysia proposed Tuesday to limit the number of vessels plying the Malacca Strait, one of the world's busiest waterways, in a move to ensure the safety of seafarers.

Deputy Prime Minister Najib Razak said 70,718 ships passed through the straits last year, a sharp 40 per cent increase from 43,965 in 1999.

"Malaysia believes there is an ultimate 'tipping point' for maritime traffic in the Straits, beyond which further increases will become not only risky but also too dangerous and costly," Najib said.

"At such a point, the cost to ensure the safety of navigation will also increase exponentially."

He said some researchers estimate that 120,000 vessels might use the Malacca Strait, which is bordered by Malaysia, Indonesia and Singapore, annually by 2015.

The narrow waterway used to be a hotspot for pirates, mostly from Indonesia's troubled Aceh province, but security cooperation from the three countries resulted in a dramatic drop in the number of attacks in recent years.

Najib said security-related incidents in the straits have become rare, with 75 cases reported in 2000 to only four in 2007. He said no piracy attacks have been reported in the first half of this year.

Najib, who is also finance minister, said Malaysia has spent more than 200 million ringgit (60.6 million dollars) to install, maintain and upgrade various navigational aids in the Straits. (dpa)