He died late Saturday night.
He was 90 and leaves behind wife and three sons, they said.
Son of K P S Menon (senior), the first Foreign Secretary of independent India and uncle of former Foreign Secretary and National Security Adviser Shivasankar Menon, K P S Menon (junior) was a 1951 batch Indian Foreign Service (IFS) officer.
He served as an ambassador to various countries, including Bangladesh, Egypt, Japan and China.
Menon had served as the Foreign Secretary of India from 1987 to 1989.
Condoling his death, Kerala Chief Minister Pinarayi Vijayan on Sunday said he was a diplomat who had contributed towards getting India’s foreign policy accepted and recognised world-wide.