The Yemeni government and its foe Houthi rebels have exchanged 29 prisoners through a tribal mediation, Yemeni Human Rights Minister Mohamed Askar said on Saturday.

"We welcome the release of prisoners ... in one of prisoner swap with the Houthi militias," Askar tweeted, giving no further detail.

Pro-government Almasdar Online news website reported that "among the pro-government released were five people who had been in prison without trial for over eight years."

Meanwhile, Abdulkader al-Murtada, Houthi head of prisoners affairs committee, Said that his group on Friday "handed over 10 government prisoners and received 19 (Houthi) prisoners through a tribal mediation at a front line near Marib province," about 170 km northeast of Houthi-held capital Sanaa.

The Saudi-backed Yemeni exiled government and Iran-allied Houthi rebels agreed on a large-scale prisoner swap deal in December 2018 as per a UN-sponsored deal, but they have since failed to implement it.

The UN Envoy to Yemen Martin Griffiths has been encouraging a prisoner release between the Yemeni warring parties as confidence-building measures to pave the way for a major political compromise to end the country's over four-year civil war.

The war has killed tens of thousands of people and pushed the Yemeni people to the brink of famine.