* Teams will go to Shanxi, Shaanxi, Inner Mongolia and major ports
* Will conduct on-site inspection of coal spot prices - NDRC
* Will show 'zero tolerance' of violations - NDRC (Adds detail, background)
BEIJING, Oct 27 (Reuters) - China's state planner said on Wednesday it and the country's market regulator had jointly formed four inspection teams to carry out "special supervision" of spot coal prices at key production regions and ports.
The move, taken by the National Development and Reform Commission (NDRC) and the State Administration for Market Regulation, is the Chinese government's latest attempt to tame high prices for coal amid China's worst power supply crunch in years.
Its campaign has already brought results on the derivatives market, with the most traded thermal coal futures on the Zhengzhou Commodity Exchange having fallen almost 50% from record highs in just over a week.
The teams will be sent to the three biggest coal mining regions of Shanxi, Shaanxi and Inner Mongolia, as well as to the major coal port of Qinhuangdao in Hebei province and other northern Chinese ports, the NDRC said in a statement.
They will "go deep" into coal mines, trading markets, storage yards and consumers, conducting on-site investigations of coal spot market prices, it said, adding they would show "zero tolerance" of violations.
Companies that have not strictly implemented measures to improve coal supply and stabilise prices will be held accountable, the NDRC said, adding that the teams would severely crack down on illegal activities such as fabricating price information and hoarding. (Reporting by Beijing Newsroom, Muyu Xu and Tom Daly Editing by Mark Potter)