SINGAPORE - The bright yellow Simpur flower beloved in Brunei, and Singapore's national flower Vanda Miss Joaquim, will grace the face of special edition $50 notes that mark a milestone in the relationship between the two countries.

The set of two new notes - comprising a B$50 bill and an S$50 one - was launched at the Istana on Wednesday (July 5) by Prime Minister Lee Hsien Loong and Brunei Sultan Hassanal Bolkiah, who is in town for a two-day state visit.

They mark the golden jubilee of an agreement that allows both countries to accept the currency issued by the other, and exchange them at par and without charge, into their own currency.

The special bills, which were jointly designed by Brunei's Abdul Ajihis Haji Terawih, and Singapore artists Eng Siak Loy and Weng Ziyan, pay tribute to the ties between the two countries.

Sultan Bolkiah noted that while the front of the B$50 and S$50 notes remain unique to each sovereign nation - Brunei's features a portrait of the Sultan, and Singapore one of its first president Yusof Ishak - the shared design on the back of these notes relects "our common values, as well as key areas of our close cooperation, including in defence education and tourism."

The designs on the back include sketches of students, among other items.

The flowers in full bloom on the front symbolise "the flourishing friendship between the two countries", a joint statement by the Monetary Authority of Singapore and its Brunei counterpart said.

The front also includes the 50th anniversary logo of the Currency Interchangeability Agreement, which came into effect on June 12, 1967.

PM Lee called this agreement a hallmark of the longstanding and unique relationship between the two countries, while the Sultan said its success is a tribute to the countries' enduring friendship.

Both higlighted how the policy of freely convertible currencies has benefitted both their economies and their peoples.

It has done away with foreign exchange risks and minimised transaction costs, facilitating the growth of trade and investment, said PM Lee.

Singapore is among Brunei's top 10 trading partners, with total bilateral trade of over $1 billion last year. And investments have grown and flowed into fast-growing areas, he said, citing how a Brunei-Singapore joint venture recently invested $20 million in Brunei's first high-tech vertical aquaculture farm. Visitor traffic and spending from both countries are also growing, noted PM Lee.

And, said Sultan Bolkiah, the agreement continues to remain relevant in facilitating trade and financial relations between Singapore and Brunei, amid changes in the global landscape. This achievement requires strong political will, and unwavering commitment to bringing about mutual benefits for their people.

"Therefore, it is our duty to nurture our relationship in the years ahead," he said, adding: "I am pleased to see our monetary authorities are exploring deeper collaboration to enhance the synergies between our financial systems."

He hoped the 50th anniversary of the agreement would provide further stability and growth, while reinforcing confidence in Singapore and Brunei's currencies.

PM Lee, referring to a visit he made to Brunei 10 years back to celebrate the 40th anniversary of the agreement, said: "I'm sure these commemorative notes will be as popular and will be picked up as quickly as the one we launched last time."

Then, Singapore and Brunei issued commemorative notes as well: two $20 bills which became hot property. The back of the notes featured Singapore's Esplanade and Brunei's Sultan Omar Ali Saifuddien mosque.

"And those limited edition, special notes became highly sought-after collectors' items," recalled PM Lee, noting that the bilateral flow of Brunei and Singapore dollars has doubled since then.

He also shared another fond memory from the visit: a morning walk with Sultan Bolkiah around the Jerudong Park Golf Course. "And Your Majesty walked so briskly that I had to try very hard to keep up," he said to laughter.

There will be more milestone anniversaries of the agreement to celebrate, he added, wondering: "What face value should the commemorative notes the next time when we reach the 60th anniversary, or 70th anniversary, or 75th anniversary?"

"You don't often have a $60 bill but I think that's an idea for our official to think about," he quipped. "They have 10 years to solve this problem and that will help our relationship and friendship to endure and to continue to blossom for generations to come."

On Wednesday, the Sultan received a rousing ceremonial welcome at the Istana for him and his wife, Raja Isteri Pengiran Anak Hajah Saleha.

He then called on President Tony Tan Keng Yam while his wife was hosted to tea by Mrs Mary Tan, who also took her around the Istana Heritage Gallery.

Dr and Mrs Tan will host a state banquet in honour of their guests on Wednesday night.

Sultan Bolkiah, who last made a state visit here in 2014, was also hosted to lunch by PM Lee and his wife Ho Ching.

About the commemorative notes

One million pieces of B$50 and two million pieces of S$50 commemorative notes will be available for public exchange at face value. In Singapore, this can be done at the branches of nine retail banks from Friday (July 7).

Banks in both countries will be co-distributing a set of two notes, accompanied by a complimentary folder.

A maximum of five sets and 10 pieces of the Singapore $50 commemorative notes can be exchanged per transaction in Singapore.

In addition to the commemorative notes which the public can exchange at the banks, an exclusive collection of five types of limited edition numismatic note sets will be available for sale. For enquiries and orders, the public can contact The Singapore Mint or access its website.

Pre-orders must reach the Singapore Mint by July 12 and will be available for collection by the public from July 18.