The exchange of 887 prisoners, brokered by the International Committee of the Red Cross, was to take place on April 11, but Yemen's Deputy Human Rights Minister Majed Fadhil, who is part of the negotiations committee, said technical issues stood in the way.
“The ICRC documents every single prisoner and conducts interviews with them individually to confirm their identity,” he told The National.
“With the large number of prisoners and despite all planning and efforts from all sides, the ICRC has said it needed a few more days to finish its interviews.”
Asked about the delays, the ICRC said the process “involves multiple layers and can be quite complex”.
“More time was needed to complete the agreed-upon procedures before the start of the operations.”
Mr Fadhil said the prisoner exchange was finalised over seven rounds of negotiations, of which two each were held in Switzerland and Jordan.
“The subject of detainees is a very important one because it is considered a trust-building issue,” he said.
The process will be carried out over three days and will take place in six different airports, he said.
Prominent Yemeni detainees are among those to be released from the Houthi side. They include Nasser Mansour Hadi, brother to Yemen's former president Abd Rabbu Mansour Hadi, former defence minister Mahmoud Al Subaihi, and Mohammad Abdullah Saleh, brother to Yemen's vice president Tareq Mohammad Abdullah Saleh.
Saudi Arabia's re-establishing of ties with Iran has also helped to provide "positive momentum" to talks and peace efforts, Yemen's Foreign Minister Ahmad Awad bin Mubarak said in an interview with Cairo TV on Sunday.
"There are direct talks between Saudi Arabia and the Houthis in Sanaa to revive the truce," he said.
"Talks between the Saudis and the Houthis never stopped even during the war, whether on political or security issues."
Hamed Ghalib from Yemen's National Resistance, which is involved in the negotiations with the Houthis, said the prisoners include 23 Saudi nationals and three Sudanese civilians.
The detainees will first be transferred between Sanaa and Aden, then between Sanaa and Riyadh, and lastly between Sanaa and Marib, he said.
"These detainees have been in captivity for nearly six years, without having any contact with their families and loved ones," Mr Ghalib said.
On Saturday, the Houthis announced the release of 13 of its prisoners from Saudi Arabia as an Omani delegation arrived in the rebel-held capital Sanaa for talks to end the eight-year war.
The 13 men were released in exchange for one Saudi prisoner, the Houthi's official in charge of negotiations on prisoner exchanges, Abdulqader Al Murtaza, said.
Talks had begun in the Jordanian capital to discuss the prisoner exchange in 2020 but had stalled several times as the war intensified.
A potential truce agreement, as discussed among Saudi officials and the Houthis, will entail the release of all prisoners of war, The National reported earlier.
The truce would extend for six months, until the end of the current year, and also include the re-opening of ports, merging of economic systems in the north and south, and payment of public servant salaries, which has been a sticking point for the warring sides.
Yemen's capital Sanaa was taken over by the Iran-backed Houthis in 2014, prompting the government to ask Saudi Arabia to intervene on its behalf and restore it to power.