Thailand's governing Pheu Thai party won last year's election partly based on a promise to improve the income of rice farmers.
The government introduced a scheme which currently pays them around 50 to 60 per cent more than market prices.
The International Monetary Fund estimates that this could amount to $3.8bn, excluding the cost of storage.
Despite the cost, the government says it will continue with the programme, because it has a duty to look after farmers.
But not everyone agrees that the benefits are worth it.
Al Jazeera's Florence Looi reports from Bangkok.