This question has already been answered several times before. For all practical purposes, as a matter of close approximation, a month is deemed to have 30 days irrespective of the actual no. of days in the month. Therefore, to arrive at the daily rate of wages in case of the fixation of the minimum wages being per month, the monthly rate has to be divided by 26 and to arrive at the monthly rate in case of fixation being per day, the daily rate of wages has to be multiplied by 30. You may find a note as above in the G.O relating to fixation or revision of minimum wages by the appropriate Governments.
Does is it mean daily rate of wages and monthly wages can be different.
According to section 7(b) IV of minimum wage act
"by such other larger wage- period as may be prescribed, and where such rates
are fixed by the day or by the month, the manner of calculating wages for a month
or for a day, as the case may be, may be indicated".
Here, government not only declare monthly wages but daily wages as well.
I think I should present my case with the help of an example.
If a company appoint two employees for the same work, one as daily wager and second as permanent worker than @300/- per day for 27 days, daily wager will earn Rs: 8100/- but on the other hand an onroll worker will get Rs: 7800/-.
Will that not against the supreme court judgment of "Equal pay for equal work".
The section you quoted is 3(3)(b) of the Minimum Wages Act,1948 relating to fixing of minimum rates of wages. If you read the above sub section carefully once again, you will understand that the appropriate Government is required to indicate the manner of calculation of the minimum wages by the other rate if it is fixed by one rate among the two viz the monthly rate or the daily rate. Therefore, it implies that the Govt can fix the minimum wages only by the monthly rate or the daily rate for any post and not by both. That's why there is an explanatory note under every such G.O indicating the method of calculation for conversion as stated by me earlier.
Coming to your example, if the minimum wages fixed is monthly rate, the on-roll/regular employee would get Rs.9000-00 irrespective of the actual no of days in a month. The daily wager appointed on the same post would earn Rs.346-15 per day ( 9000/26) and not Rs.300/=per day. You know well that you can not allow a workman whether he is a regular or a casual on daily wages to work continuously all the 7 days in the week as per the provisions of rule 23 of the Minimum Wages (Central) Rules,1950 or the corresponding State Rules as the case be. In this manner the parity between the monthly earnings of the regular workman and the daily wager holding the same post would be maintained.