Indonesian President Joko Widodo wants Australia to become a full member of ASEAN, signalling Friday he is keen on Canberra playing a bigger regional role in defence, trade and security matters.
His comments come with Australia hosting a special summit of Association of Southeast Asian Nations (ASEAN) leaders in Sydney, as China increasingly flexes its muscle and the threat of violent extremism grows.
"I think it's a good idea," Widodo told the Sydney Morning Herald, referring to Australia joining ASEAN -- the first time an Indonesian president has endorsed the concept.
"Because our region will be better, (for) stability, economic stability, and also political stability. Sure, it will be better."
Australia has been a dialogue partner of ASEAN, which groups Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Vietnam, since 1974.
They began biennial leaders' summits in 2016, with the first in Vientiane.
In a report last month, the Australian Strategic Policy Institute argued that Canberra should aim for ASEAN membership by 2024 -- its 50th anniversary of being a partner -- and use the Sydney summit as a launch pad.
"As the geo-strategic and geo-economic pressures build in Asia, ASEAN, as a middle-power grouping, needs the extra middle-power heft offered by Australia and New Zealand," it said.
"The Sydney summit is the moment to launch the long conversation about Australia joining ASEAN."
Australian Prime Minister Malcolm Turnbull said he was "very warmed" by Widodo's comments, but stressed "ASEAN matters are matters for ASEAN".
"We have the greatest respect for ASEAN, the way it reaches its own conclusions," he said ahead of a bilateral meeting with Cambodian leader Hun Sen.
"We are a dialogue partner with ASEAN and we respect that centrality of ASEAN and its significance and fundamental importance, central importance, in our region."
Speaking at a press conference alongside Turnbull, Singapore Prime Minister Lee Hsien Loong said he was keen to "deepen ties between Australia and Southeast Asia more broadly".
"Australia believes its future lies in Asia, took steps to become ASEAN's first dialogue partner in 1974, and Singapore has taken steps to help keep the region open," said Lee, the 2018 ASEAN host.
"As ASEAN chair, Singapore will continue to encourage Australia's engagement with ASEAN, and we will discuss taking the partnership forward."
Widodo, who will reportedly have a private dinner with Turnbull at his harbourside home on Saturday, singled out close co-operation with Canberra on counter-terrorism.
He said he regularly spoke on the phone with Turnbull to resolve issues such as the threat posed by Islamic extremists who last year seized the Philippines' city of Marawi.
"We have good co-operation on Marawi, not only with Australia but also with Malaysia, with the Philippines, with Brunei," he said.
"You know that no country is invulnerable from terrorism or extremism."
Countering the threat of violent extremism and ways to choke terrorist financing are key themes of the Sydney summit.
The warming of ties between Indonesia and Australia follows a period of rocky relations due to Jakarta's execution of Australian drug smugglers and Canberra's policy of turning migrant boats back to Indonesia.