KUALA LUMPUR, Jan 19 — Singapore's reaction to the Johor mentri besar's visit near disputed waters between Malaysia and Singapore was disproportionately "severe”, Prime Minister Tun Dr Mahathir Mohamad has said.

Dr Mahathir acknowledged Johor Mentri Besar Datuk Osman Sapian's recent visit was without the federal government's blessings.

"Well the Mentri Besar went without our permission. He thought that it was Johor waters, that's why he went there.

"I mean the reaction to his going there is quite severe, as if you are going to war. I mean he is going to go in a ship into neutral water,” he said during a dialogue session after his speech at the prestigious Oxford Union in UK.

When a member of the audience argued that the Johor mentri besar's visit was not in neutral waters but within waters that Malaysia allegedly only claimed last year, Dr Mahathir replied: "It is not Singapore water either, it is international water and the mentri besar can go into international water without Singapore sending warships to chase him away.”

On January 9, Osman visited Malaysian Marine Department vessel MV Pedoman, with Singapore's defence minister reportedly admitting on January 15 to have sent Police Coast Guard (PCG) and Republic of Singapore Navy (RSN) vessels to respond to the latter's visit.

Osman"s entourage had only comprised of Malaysian civilian vessels.

The MV Pedoman ship was anchored within Johor Baru’s new port limits, but Singapore is currently disputing the limits claim and has expanded its own port limits to overlap that of Johor Baru.