Their Majesties the King and Queen have sent a condolence letter to Singaporean President Tony Tan over the death of Lee Kuan Yew.
"The queen and I have learnt with deep sorrow of the demise of His Excellency Mr Lee Kuan Yew, former prime minister of the Republic of Singapore.
"We wish to extend to your Excellency and members of the bereaved family, as well as the people of the Republic of Singapore, our sincere sympathy and heartfelt condolences for the irreparable loss of the founder of the republic whose sacrifice and dedication led to the birth and prosperity of the nation,'' the letter says.
Lee, Singapore's first and longest-serving prime minister, died on Monday at the age of 91.
World leaders have offered condolences to Singapore leaders and their people over the passing of the country's founding father.
The mourning period was scheduled from March 23-29 and a state funeral service will be held on Sunday.