Her sister, Stephanie Muite, did not specify the nature of her ailment.
Ms Muite spoke at Nanyuki Police Station where she had gone to seek police escort to transport the body by road to Nairobi.
Foreign Affairs Cabinet Secretary Amina Mohamed had mourned the passing on of Mrs Wamalwa.
The widow of former vice president Kijana Wamalwa, Yvonne Wamalwa, died on Thursday morning at Nanyuki Cottage Hospital while undergoing treatment.
Her sister, Stephanie Muite, said Mrs Wamalwa developed complications and was rushed to hospital where she passed on moments after being admitted.
She did not specify the nature of her ailment.
“We have been staying with Yvonne at my home at Ichuga Village since October last year and she has been [going to] Outspan Hospital in Nyeri Town for treatment.
“This morning her conditioned worsened and she passed on at Nanyuki Cottage Hospital,” said Ms Muite.
LEE FUNERAL HOME
Ms Muite spoke at Nanyuki Police Station where she had gone to seek police escort to transport the body by road to Lee Funeral Home in Nairobi.
The management of Nanyuki Cottage Hospital declined to talk journalists on Mrs Wamalwa’s death and referred reporters to the family.
The body remained at the hospital for five hours before it was loaded into a hearse and taken to Nanyuki Police Station.
Laikipia County Police Commander Simon Kipkeu said they were assisting the family to transfer the body to Nairobi.
Earlier plans to airlift the body to Nairobi were abandoned with police saying the arrangements had been called off since it was likely to take long.
“We have opted for road transport since it will only take about two hours,” said Mr Kipkeu.
AMINA MOURNS YVONNE
Meanwhile, Foreign Affairs Cabinet Secretary Amina Mohamed had mourned the passing on of Mrs Wamalwa.
In a statement, Ms Mohamed eulogised Mrs Wamalwas as “a consummate diplomat, an expert negotiator, and a well-spoken, passionate patriot”.
Until her demise, Mrs Wamalwa was the deputy director in the Asia and Australasia Directorate in the Ministry of Foreign Affairs.
Ms Mohamed also praised Mrs Wamalwa as a skilled negotiator, a skill she said was evident during the United Nations Conference on Trade and Development (UNCTAD) and The Sixth Tokyo International Conference on African Development (TICAD) conferences held in Nairobi.