Thailand's Prime Minister Prayuth Chan-o-cha has postponed his visit to Singapore this week, according to a statement from Singapore's Ministry for Foreign Affairs.

General Prayuth was scheduled to make his first official trip to the Republic from Tuesday to Wednesday to attend the Singapore-Thailand Leaders' Retreat, at the invitation of Singapore's Prime Minister Lee Hsien Loong.

He will attend the state funeral for Mr Lee on Sunday.

However, both sides had agreed to the postponement of the visit owing to the health of Mr Lee Kuan Yew, Singapore's founding father, the statement said.

The visit will be resumed at another convenient time, it added.

Mr Lee Kuan Yew, 91, died at the Singapore General Hospital on Mondary, March 23, where he had been warded for severe pneumonia since Feb 5.