Two king sago palm trees standing in Singapore's Japanese Garden are "firm and strong", just like the ties between Singapore and Japan.

Both Emperor Akihito - who in 1970 planted the trees with his wife Empress Michiko when they were Crown Prince and Princess - and visiting Singapore President Tony Tan Keng Yam talked about these trees last night as they toasted 50 years of Singapore-Japan relations.

"Much like the palm trees, Singapore-Japan relations have blossomed and strengthened over the past 50 years," said Dr Tan during a state banquet at the Imperial Palace, hosted by the royal couple.

Today, the two countries "enjoy a close and enduring friendship", he added.

Dr Tan and his wife, Mrs Mary Tan, were hosted to a six-course French dinner at the banquet attended by about 140 people, including envoys and businessmen from both countries.

In a speech, Emperor Akihito recalled the royal couple's first visit to Singapore in 1970.

He said: "Every time we visited Singapore since then, we witnessed the dramatic progress that you had made in the intervening years. Now, more than half a century since Singapore's independence, you have succeeded in creating a beautiful, affluent nation."

The royal couple had visited as state guests in 1981 and 2006.

Singapore's progress, he said, has been "accompanied by similarly striking advances in the bilateral relations between our two countries" - and this is in part thanks to the efforts of leaders such as founding Prime Minister Lee Kuan Yew and former president S R Nathan.

He expressed his condolences for "the loss of two figures who... greatly contributed to the fostering of friendly and cooperative ties with Japan". Mr Lee died in March last year, and Mr Nathan, this August.

However, even as ties continue to grow, he stressed that Japan "must never forget" the lives that were lost in Singapore during World War II and the hardships suffered by its people.

Dr Tan, meanwhile, noted the two countries have come to share a "high level of familiarity and trust".

Beyond their common interests, they also provide joint technical assistance to other countries via the Japan-Singapore Partnership Programme for the 21st Century. This has benefited more than 6,000 people from over 90 countries, the Emperor added.

Dr Tan noted that economic ties too are multifaceted, with about 5,000 Japanese companies registered in Singapore. He added that he was "pleasantly surprised" to learn that the annual Christmas light-up along Orchard Road has been sponsored by Japanese technology company Hitachi for the last 26 years.

People-to-people ties are also robust, with ever-increasing tourist numbers and a wealth of cultural exchange events. The Japanese Association in Singapore marked its 100th anniversary last year.

Some 40,000 Japanese citizens call Singapore their home, Emperor Akihito said, while Dr Tan noted that the bond between the two peoples was "most evident" after the March 11, 2011 earthquake and tsunami disaster that devastated vast areas of north-eastern Japan.

Singapore's total relief efforts then raised $35.7 million - one of the Republic's largest disaster relief contributions to a single country - and covered reconstruction and upgrading projects.

The two nations can "reflect with great pride and satisfaction" over the last 50 years, said Dr Tan.

"We can continue to achieve more together as we look forward to many more years of friendship and cooperation," he added.