The ceasefire, aimed at ending the chaos and bloodshed that has gripped Yemen since March 2015, came into effect on Saturday following the intervention of US Secretary of State John Kerry.
But despite a lull in air strikes on the rebel-held capital, both parties traded accusations over hundreds of violations.
The Saudi-led coalition said the truce ended at midday (0900 GMT) Monday, and accused Iran-backed insurgents of repeatedly breaking it.
"There is no respect (for the truce), only violations," coalition spokesman Major General Ahmed Assiri told AFP.
"There have been more people killed in (the southwestern city of) Taez and more attacks with surface-to-surface missiles, so automatically the conditions are not there" for prolonging the ceasefire deal, he said.
"At the military level, for the moment, we have no orders to extend the ceasefire. It's over."
The coalition had said the truce could be renewed if the rebels abided by the deal and allowed aid deliveries to besieged cities.
But both sides have accused each other of incessantly breaking the conditions of the deal, and violence flared as its expiration loomed.
Fifteen rebels and nine loyalist troops were killed in clashes overnight in and around Taez, military and medical sources said.
Four civilians were also killed and 11 others wounded in rebel bombing of loyalist-held neighbourhoods, the sources said.
Early Monday, forces loyal to Hadi attacked Shiite Huthi rebels and their allies on the western outskirts of Taez, according to military officials.
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The offensive targeted an air defence base, the officials said, while witnesses reported loud explosions.
Four of the Huthi casualties were killed in an air strike by the Saudi-led coalition.
Coalition warplanes hit rebel positions in Nahm, north of rebel-held capital Sanaa, and in the Huthi's heartland in Saada province, witnesses said.
And warplanes also conducted numerous sorties over Sanaa early Monday.
- Trading blame -
The ceasefire was the latest international effort to put an end to Yemen's 20-month conflict, which the United Nations says has killed more than 7,000 people and wounded nearly 37,000.
Yemen's Huthi rebels overran Sanaa and other parts of the impoverished Arabian Peninsula country in September 2014, prompting the Saudi-led coalition to intervene six months later in support of President Abedrabbo Mansour Hadi.
Pro-Hadi forces said Monday they repelled a rebel attack on their positions in Sarwah, in Marib province, east of the capital.
The ceasefire appeared to be shaky from the outset, and Assiri accused the rebels of 563 violations in Yemen and an additional 163 cross-border violations in Saudi Arabia.
A spokesman for renegade Yemeni troops allied with the rebels accused the pro-Hadi forces of more than 100 ceasefire violations.
Local aid activists and witnesses also accused the rebels of blocking a relief convoy of 18 lorries from reaching the city of Taez on Sunday.
The UN children's agency UNICEF says nearly three million people in Yemen are in need of immediate food supplies, while 1.5 million children suffer malnutrition, including 370,000 enduring very severe malnutrition that weakens their immune system.