Prime Minister Malcolm Turnbull has stressed the need for a "decisive" regional response to terrorism, saying the threat is worsening.
Mr Turnbull and his wife Lucy began their visit to Singapore on Friday with a visit to Kranji war cemetery where World War II allied forces are buried, followed by a trip to the botanic gardens where a yellow orchid was named in their honour.
Turnbull was a keynote speaker at a security summit, where he discussed the growing threat of terrorism in the region and the need for a rules-based order, particularly around issues like the hotly contested South China Sea.
"The threat of Islamist terrorism gets worse in our region," Mr Turnbull told reporters.
Referring to the ongoing battle in the southern city of Marawi in the Philippines between IS-linked terrorists and government forces, Mr Turnbull said the threat of returning foreign fighters was a "very real one" in the region.
"Our response must be as decisive, emphatic and global as the threat that is presented to us."
Australia would continue to support the Philippines through intelligence sharing, he said.
Australian National University defence and strategic expert John Blaxland said the prime minister's speech at the summit later on Friday would be significant.
He said nations in the region were struggling to gauge the "fickle nature" of American foreign policy and whether they could rely on the US to engage in ongoing security challenges.
"Most countries in Southeast Asia are very circumspect about being too supportive of the US, as they are not sure how committed the US is to staying the course," Professor Blaxland told AAP this week.
He said Australia served as an "interesting indicator" on its close ally America.
"(Turnbull's speech will) influence their thinking about the degree of latitude they have from deviating from what they know China wants," he said.
When asked if US President Donald Trump's announcement to pull out of the Paris agreement would add to this uncertainty, Mr Turnbull said "the United States commitment to peace and the rule of law is an enduring one and will be an enduring one."
Outside the summit, Mr Turnbull will continue to build on Australia's defence and trade relationship with Singapore, in meetings with President Tony Tan Keng Yam and Prime Minister Lee Hsien Loong.
Announcements regarding business visas between the two countries to allow further engagements and cyber-security co-operation are also expected.
