Malaysia cannot unilaterally build a "half-bridge" to Singapore to replace an existing link as international law requires mutual consent by affected parties, a minister said.

Second Minister for Foreign Affairs Raymond Lim reiterated Singapore's position in Parliament following statements by Malaysian officials it was their right to build their own half of a full-bridge intended to supplant a causeway currently linking the neighbours.

"Singapore does not accept that Malaysia has a right to demolish its side of the causeway unilaterally and replace it with a half-bridge," Lim said, stressing even a half-bridge would affect Singapore.

He said Malaysia has yet to formally respond to Singapore's position.

Comments by Malaysian officials that they intend to unilaterally proceed with the construction of the half-bridge "will not be helpful" to ongoing talks about the possibility of a full span, Lim added.

Last month, Malaysian Works Minister S Samy Vellu said Malaysia will continue work on its half-bridge even before its neighbour has agreed to build the other half.

Malaysian Deputy Prime Minister Najib Razak also said "we view the bridge as our right and no one can deny us that right."

Singapore maintains that Malaysia's proposal to replace the causeway with a new link would be costly and have "no significant benefits" to the island-state.

Areas of vital importance

However, in the spirit of "good neighbourliness," Singapore said it was prepared to consider Malaysia's proposal if there is a "balance of benefits".

Lim said Singapore's position was made after seeking expert legal advice.

"Any major work related to the causeway - on which also are sited the pipelines supplying water to Singapore - will affect both Singapore and Malaysia in a variety of areas of vital importance to both countries," he said.

Singapore gets about half of its drinking water supply from Malaysia.

Lim cited a case in 2003 in which Malaysia asked the International Tribunal on the Law of the Sea to stop Singapore from undertaking reclamation work within Singapore territory.

"Malaysia's action was guided by the principle that any major work in the Johor Strait, even if done within the sovereign territory of Singapore, could affect Malaysia," Lim said.

Malaysia and Singapore have squabbled for years over a variety of issues, but while other bilateral feuds have been settled amid a thawing in relations over the past year, the bridge remains an outstanding problem.