It's estimated more than 375,000 people have been affected, with over 9,000 homes evacuated.
The international humanitarian agency Care is working with local authorities to assess the damage in Rattanakiri Province, which is one of the worst affected areas.
Speaker: Stav Zotalis, Care's country director in Cambodia
ZOTALIS: The heavy rains have been since the third week of September and there's been flooding throughout the country. In addition, in Rattanakiri Province, in the northeast of Cambodia, where Care operates have been affected also by flash floods and then flooding of the two rivers.
LAM: So what can you tell us about Rattanakiri Province?
ZOTALIS: Well, Rattanakiri Province has seen extensive damage to crops, there's also been schools and health centres damaged, hectares of rice seedlings have been inundated and, until the rain clears, it will be very difficult for us to know the full extent of the damage.
LAM: And Stav, given the fact that many people have lost their homes, may we assume then that much of that province has been evacuated?
ZOTALIS: Evacuations have happened throughout the country. There's been, as you said, 39 confirmed deaths, but reports are coming in about more people that have unfortunately died and there have been throughout Cambodia about more than 10,000 families that have been evacuated to higher ground.
LAM: And Stav, you're speaking to us from Thailand now. But just before you left Cambodia, what was the situation like, what were the areas of greatest need?
ZOTALIS: Well, 15 provinces have been affected by both floods and flash floods and the heavy rains are continuing. The Mekong River in some parts of Cambodia, remains among emergency levels. The Unfortunately, it coincided with a large religious festival, and so lots of people have been travelling and the government has called for support to flood victims and we are monitoring the situation very closely.
LAM: And imagine many of the communities that have been affected are quite poor. What is Care doing for them?
ZOTALIS: Care works in some of the poorest places in Cambodia, including in Rattanakiri. We're working to move people where needed and then provide them much needed assistance.
This coming period is going to be absolutely critical to avoid further loss of life, but also to help people getting access to clean water, to flood, and to other essential services.
LAM: And as far as you know, are the floodwaters beginning to recede or are many provinces still flooded?
ZOTALIS: Yes fortunately, the disastrous floodwaters are beginning to recede slowly and the water in Phnom Penh has come down and in some other parts of Cambodia, but heavy rains is still predicted, so we're watching with caution.
LAM: And Stav, when do expect the situation to ease a little bit for the Cambodians?
ZOTALIS: We are hoping this week that the floodwaters will begin to recede further and in that situation, we're be able to do a further assessment and also provide much needed support to areas where Care operates in Cambodia.
LAM: And Stav, you are, of course, Care's Country Director in Cambodia. You're currently speaking to me from Thailand,
Thailand, of course, has also been affected by the floods. How are they coping?
ZOTALIS: The government's also on alert here. There have been fewer deaths in Thailand, but the Bangkok residents were (words indistinct) a couple of days have been warned over a high tide.
LAM: There's also a sense that because Bangkok, the capital, has so far not been traumatised by this year's floods that the provinces where the flooding is the main worry have been ignored by the media. Would that be a fair assessment?
ZOTALIS: Well, the floods are affecting about 28 provinces in Thailand, including Chiang Rai and Rayong and there have been 34 deaths here and also like Cambodia, devastation of farmland and property damage.