Chief secretary K Shanmugam issued the order, following a proposal from the revenue department, allowing resumption of work related to irrigation and water conservation.
However, the order says work should not be taken up in Covid-19 containment zones and red blocks.
It will also be subject to the conditions that not more than one-third of the required number of labourers are mobilised, workers are provided with masks and strict physical distancing guidelines are followed.
Authorities said 56 types of agriculture and allied work would be taken up as per the guidelines.
More than 82.67 lakh active workers stand to benefit from the order.
The government recently enhanced the wage of MGNREGA workers in the state from Rs. 229 to Rs. 256.