The Namibia Press Agency reported that Iyambo fainted while seated in the tent reserved for dignitaries, as Nghidinwa’s casket was being lowered into the ground.
The news agency said the 81-year old Iyambo was rushed out of the tent by his bodyguards.
Later, Presidential Affairs Minister Frans Kapofi confirmed the incident to the national broadcaster NBC.
He said the vice-president fainted due to fatigue and low blood pressure.
“The VP was doing well the whole of this morning. He arrived (at the funeral) and addressed the mourners at the grave site. And together with other dignitaries, they went to the grave site to do the final send-off. As you know, this place is very hot and that there was a setback – the VP almost collapsed. According to the professionals, it was about fatigue and low blood pressure,” Kapofi said.
He said Iyambo recovered from the ordeal and managed to board his plane back to the capital Windhoek.
In September 2016, Iyambo also fainted just after addressing the community of Tsumeb in Oshikoto region, at a belated Heroes Day celebration.
At the time, Oshikoto Governor Henock Kankoshi said the VP fainted because he did not eat the whole day.
Nghidinwa who was 65 died on 15 January, after being admitted at a private hospital in Windhoek late last year.
She was accorded a state funeral.
A former nurse, she served as lawmaker for the ruling SWAPO Party from 2000 to 2015, and served as Home Affairs and Immigration Minister (2005-2012) and Gender Equality and Child Welfare Minister (2012-2015).