Countries dealing with Singapore should not take the Republic's consistency, and what some would say predictability, for granted, Foreign Affairs Minister Vivian Balakrishnan said.

"We will always take appropriate measures to safeguard our interests. And any country dealing with Singapore must not assume that it is cost-free to embark on any adventures or antics against us.

''There will be consequences,'' he stressed.

Speaking in Parliament yesterday on current Singapore-Malaysia tensions over territorial waters and airspace issues, Dr Balakrishnan said it was the reason Singapore postponed a planned meeting between National Development Minister Lawrence Wong and Malaysian Minister for Economic Affairs Azmin Ali, as well as officials on both sides.

The Joint Ministerial Committee (JMC) for the development of Iskandar Malaysia was scheduled to meet yesterday.

Singapore postponed it after an intrusion by Johor's Menteri Besar Osman Sapian, who had visited a Malaysian vessel in Singapore's territory last Wednesday. The act went against the spirit of an agreement concluded by the foreign ministers of both countries just a day earlier.

Dr Balakrishnan told the House: ''I hope members appreciate this fine line that I am trying to follow - to be resolute but to be calm, to quietly but clearly protect our interests. And it doesn't mean we do not have sharp elbows.''

He was replying to Mr Vikram Nair (Sembawang GRC) who, while commending the Government's calm and sensible approach to the tensions, was concerned that Malaysia's actions were not consistent.

''If one side is being sincere (but) the other side is not or is not able to follow through with actions, what can we do?'' he asked.

Echoing a similar sentiment, Mr Alex Yam (Marsiling-Yew Tee GRC) noted that each time Malaysia commits a provocative act, Singapore is firm, saying ''don't do it again''.

But will the time come when Singapore will make it clear that further provocation will be met with an equal reaction, he asked.

Dr Balakrishnan said: ''I want to clear up this confusion that they are the ones who have the licence to provoke and that we respond, but without an equal and opposite response.''

But he cautioned: ''Red lines are not something you draw lightly and not something which you should pronounce publicly without having carefully thought through all the consequences and without communicating those considerations clearly and unambiguously with the person you are negotiating with or the other side, and I hope members of this House and Singaporeans will understand that some of these are best conducted behind the scenes quietly, and that is why I do not believe in megaphone diplomacy.''

In the end, it is Singapore's reputation for consistency and constancy that adds to the Republic's reputation of reliability and integrity.

''So, that is the way we deal,'' Dr Balakrishnan said.

''Sometimes it may come across as we are boringly consistent and we seem to studiously avoid chest thumping and other manifestations of nationalism. But I would submit that this is the appropriate posture for a small, tiny nation state like Singapore.''

It does not mean Singapore is passive or is giving in, he added.

Different factors are at play when such negotiations are conducted. For example, ''knowing we have a credible and strong SAF (Singapore Armed Forces) again makes diplomacy much easier''.

Ultimately, the objective is for the spirit of candidness, sincerity and openness to prevail for the issues to be resolved.

''I can see a way forward to resolve all of them,'' he said. ''So long as there is a possibility, a probability of resolving it, our current tack of making sure the situation remains calm... is still the appropriate thing to do.''

On a positive note and in response to a question by Workers' Party chief Pritam Singh (Aljunied GRC) on whether the Malaysian government is sincere in wanting to resolve the tensions, Dr Balakrishnan said he has found Foreign Minister Saifuddin Abdullah and Minister Azmin to be sincere, constructive and helpful.

In some instances, goodwill prevails, he said to Mr Liang Eng Hwa (Holland-Bukit Timah GRC), who asked if the Johor authorities appreciate Singapore's efforts to supply additional treated water to the Malaysian state.

Singapore had supplied additional treated water between Jan 2 and 4 at Johor's request after pollution disrupted its production.

Dr Balakrishnan said that under the 1962 Singapore-Malaysia water agreement, Singapore is obliged to sell to Malaysia only 5 million gallons a day. In practice, it supplies Johor 16 million gallons of treated water daily.

''Why do we do it? We do so out of goodwill,'' Dr Balakrishnan said, and added: ''We hope this goodwill will be reciprocated.''