Cambodian soldiers attacked a Thai outpost at Phu Ma Khua in the disputed border area several times overnight, but were repulsed, army spokesman Sansern Kaewkamnerd said on Wednesday.
Col Sansern said there were no Thai casualties.
The Cambodian attack began about 8pm, when they threw hand grenades into the Thai position.
About 9pm, Cambodian soldiers tried to break through the fence around the post, but were repulsed by Thai soldiers throwing hand grenades.
Cambodian soldiers probed the Thai position again about 10pm with more hand grenades, and the Thais retaliated in kind.
About 2am on Wednesday, Cambodian forces renewed the attack, this time directing machinegun fire, mortar rounds and rocket-propelled grenades at the Thai position. The Thai troops returned fire and pinned down the attackers, he said.
Cambodia attacked again, unsuccessfully, between 3.50am and 4am.
Sporadic exchanges of fire continued until 5.25am on Wednesday.
There were no casualties on the Thai side, which held on to the position, Col Sansern said.
The army spokesman said the attacks showed Cambodia were paying no attention to the United Nations Security Council's call for a permanent ceasefire.
The Cambodian troops' intention had clearly been to take the Thai position, he said.