Several world leaders and dignitaries sent birthday greetings to Singapore's former Prime Minister Lee Kuan Yew on his 90th birthday, local media reported on Monday.

According to the city-state's Ministry of Foreign Affairs, the United Kingdom's Queen Elizabeth II noted that Lee's life has been inextricably interwoven with the history and development of Singapore.

"It is notable that this year also marks the 50th anniversary of Singapore's independence from the UK and I am delighted that the links between our countries remain so strong," she added.

Germany's Chancellor Angela Merkel also sent her greetings. She said for over 50 years, Lee has been "a decisive figure" helping to shape Singapore's destiny and leading the country to peace and prosperity.

"It is in no small measure thanks to your prudent policymaking that the regional association ASEAN has become a force for reconciliation and stability in Asia," local media quoted Merkel as saying.

She recalled the "stimulating conversation" she had with Lee during a meeting in 2011 when she visited Singapore. She also said Singapore will remain "a key partner" for Germany in Asia.

Former Chinese vice-premier Li Lanqing expressed his "deep respect" for Lee's "outstanding contributions to the independence and prosperity of Singapore, and to the friendship and cooperation of China and Singapore."

In 1994, the then Chinese Vice Premier Li Lanqing and Singapore Senior Minister Lee Kuan Yew signed the agreement on the joint development of Suzhou Industrial Park in Suzhou, the first flagship bilateral project between the governments of the two countries.