A truce in Yemen started at 21:00 GMT on 10 April, ahead of UN-sponsored peace talks in Kuwait on 18 April.
There have been reports by several local news sources, however, that the ceasefire has already been violated.
Until now, we do not know if the violations were intentional, but we will evaluate in the next few hours to see if they were, Yemens Foreign Minister Abdulmalik al-Mekhlafi told the Saudi-based Al-Arabiya news channel.
If these violations prove to be intentional, we will retaliate, he said.
A spokesman for the Saudi-led coalition urged the rival, Iran-allied Houthi rebels to respect the truce, which he said the Yemeni government and its GCC partners would adhere to.
But if there is any violation of this ceasefire, we will have the right to retaliate, to assess the situation at that time and take whatever steps are necessary to stop these violations, Saudi Brigadier-General Ahmed al-Asiri told UK news agency Reuters.
Coalition spokesman Al-Asiri said Yemeni military officials and some militia representatives had met over the past two days in southern Saudi Arabia to prepare for the ceasefire, and had signed agreements on how it would be implemented and monitored.
The halt in fighting is intended to facilitate the delivery of much-needed humanitarian aid.