The petitioners were not the party whose rights and liberties had allegedly been violated by the scheme, the court ruled.
Court spokesman Pimol Thampithakpong said the ruling was unanimous, with a vote of 9-0.
The petition, which sought a court injunction halting the scheme, was filed by academics and students from Thammasat University and the National Institute of Development Administration (Nida) led by Adis Israngkura na Ayutthaya, dean of Nida's School of Development Economics.
The petition said that the pledging principle required that the pledged price should be lower than the market price, to allow farmers to redeem their rice when the price goes up. Under the rice pledging scheme, the government intentionally fixed a much higher pledged price than the market price, with no intention of farmers ever redeeming their rice.
In doing so, the government was becoming the largest rice trader in the country, in competition with the private sector. It was a monopoly and therefore destroyed the trade system, affecting the rice production system and distorting market mechanisms, the petition argued.
Mr Pimol said the court had performed its duty with impartiality and without political pressure. If the petitioners wanted to petition another agency, they should first find out if it had the power to take it up for consideration, he added.
In this case the Constitution Court decided it does not have the power under Section 212 of the constitution to take the petition up for consideration. The petitioners were not parties whose rights and liberties had been violated by the implementation of the scheme, Mr Pimol said.
Earlier Wednesday, Prime Minister Yingluck Shinawatra said she would order the Commerce Ministry to hold a press conference to give details on sales of eight million tons of pledged rice in government-to-government (G-to-G) deals, including the countries which signed a memorandum of understanding, the opening of letters of credit and deliveries of the rice.
Ms Yingluck said some information in the G-to-G may be confidential, but the government would make as much as possible public to ensure a better understanding.
Asked about the alleged corruption in the implementation of the scheme, the prime minister said Deputy Prime Minister Chalerm Yubamrung had been assigned to investigate.
Asked if ministers in the economic team agreed with the scheme, she said they should because it is one of the government's policies.
Deputy Prime Minister for economic matters Kittiratt Na-Ranong took the same tone.
Mr Kittiratt, also the finance minister, said on Wednesday afternoon that the rice pledging scheme is a good policy, even though it was disputed by some academics.
“This programme enables an increasein the incomes of rice farmers through the government’s rice supply management mechanism.
“Rice export growth this year might be seen as having a contractionm but it can be clearly seen that this year the export prices of rice are at a historical high.
“The government’s supply management system can help to substantially raise export prices of rice on the world market,” he said.
Mr Kittiratt said legal action was being taken against those involved in the reported irregularities and corruption under the rice scheme. The government had the real intention to help rice farmers and any irregularities must be eliminated.
However, as a consequence, Thais may have to pay more for rice in the shops, he said. But it was for the betterment of poor farmers.
The government would work with farmers to help them increase rice production per rai. The Irrigation system would as much as possible to enable farmers to grow more rice crops each year, he said.
In highland areas, the farmers will be supported to grow other cash crops instead of rice, including energy plants, he said.