The gathering will be attended by defence ministers and armed forces chiefs from about 20 countries, including the world's most powerful nuclear-armed nations, who are meeting for informal talks at the hotel.
Dubbed the Asia Security Conference: The Shangri-La Dialogue, the event is the only inter-governmental forum in Asia focusing on defence and security-related topics.
Senior Minister Lee Kuan Yew will launch the three-day conference with a keynote address on Friday.
The discussions will be Asia's first major security conference since the end of the war in Iraq.
Defence analysts noted that the heavy emphasis on defence matters at the event is timely in view of the recent resurgence in terrorist activity, as seen by suicide bomb attacks in Saudi Arabia and Morocco.
Dr Tim Huxley, senior fellow for Asia-Pacific Security at the IISS, said: 'This year, the struggle against terrorism in South-east Asia, heightened concerns over nuclear proliferation in the Korean peninsula and continuing tension between India and Pakistan are likely to form key elements of the discussions at the conference.'
He will attend the conference as part of a delegation led by the institute's director, Dr John Chipman. In 2000, Dr Huxley, a specialist in Asian security issues, published the bestseller, Defending The Lion City: The Armed Forces Of Singapore.
The Shangri-La Dialogue has added value for confidence-building as several delegations who attended last year's event hosted informal meetings outside its formal proceedings.
Last May, when India and Pakistan looked poised to start a nuclear war against each other, Indian Defence Minister George Fernandes used the opportunity to hold such sessions with defence planners from various countries on the margins of the conference.
Such meetings form an essential element of defence diplomacy.
According to the IISS, these little gatherings at last year's dialogue helped avert the risk of war on the Indian subcontinent by facilitating face-to-face meetings between defence officials who would otherwise not have a chance to meet.
Dr Huxley noted: 'Without this event, Asia would lack an inter-governmental forum in which defence ministers can lead the discussion or where defence issues are at the top of the agenda.
'So, the Shangri-La Dialogue is an emergent regional security institution mildly disguised as a conference.'
Dr Tony Tan, Deputy Prime Minister and Minister for Defence, said the willingness of top defence officials to travel here for the conference reflects their confidence in the security measures Singapore is taking to safeguard those attending the talks.
'These are people who know this part of the world very well. They are knowledgeable, they know about the security situation, they know about Sars,' Dr Tan said.
'The fact that the conference is being held and those coming here are at such a high level is, I think, a testament to the confidence they have in our security agencies and in the measures we're taking to ensure that nobody attending will get Sars.'
He made the point last Friday after reviewing homeland security and counter-terrorist measures devised by Singapore's defence science community.
'It's a good sign, but this reputation is not earned by chance,' he pointed out. 'It's earned by hard work and by taking all necessary measures both on the security and health side.'
