Indonesian Foreign Minister Retno Marsudi is in Singapore for a two-day visit, during which a landmark sea border treaty between the two countries will come into force.
Ms Retno, who arrived yesterday, will meet her counterpart, Dr Vivian Balakrishnan, to exchange ratification instruments for the treaty today, said the Foreign Ministry.
This will formalise the pact, which was signed in 2014 to provide clarity on Indonesia and Singapore's sovereignty over the bustling Strait of Singapore. It demarcates a 9.5km-long sea border along the waters between Changi and Batam island.
The treaty was ratified by the Indonesian Parliament last December, and is the third of its kind between the two countries.
They first agreed on the maritime boundary along the central part of the Singapore Strait in 1973, and in 2009 signed another pact on the western section, between Indonesia's Pulau Nipa and Singapore's Sultan Shoal.
With the latest treaty in place, the three pacts account for a continuous 67.3km-long sea border in the Singapore Strait.
The two foreign ministers will also hold a press conference this afternoon, during which they are set to announce the start of celebrations of the 50th anniversary of ties between the two countries.
Ms Retno will have a four-eyes meeting with Dr Balakrishnan, who will also host her to lunch today.
They are likely to follow up on issues raised when Indonesian President Joko Widodo met Prime Minister Lee Hsien Loong during the Leaders' Retreat in Semarang, Central Java, last year.
These include tourism and energy cooperation, as well as the setting up of the Indonesia-Singapore Business Council, among others.
Today, Ms Retno will make a courtesy call on PM Lee at the Istana. She will also speak about her country's foreign policy under President Joko at the Distinguished Public Lecture organised by the S. Rajaratnam School of International Studies.