The court instruction comes ahead of Manjhi's trust vote on February 20.
The direction was given by a division bench comprising justices Iqbal Ahmad Ansari and Samrendra Pratap Singh.
"Respondents should not take any decision having financial implications except for routine matter," the bench ordered on a PIL filed by JD(U) legislator Niraj Kumar.
The court fixed February 19 as the next date of hearing.
Besides Manjhi, there were three other respondents including the chief secretary, the principal secretary to the governor and the principal secretary to the chief minister.
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He highlighted decisions like reserving work for SC/ST contracts up to Rs 70 lakh, lowering attendance for school students from 75 per cent to 60 per cent for general category and 55 per cent for SC/ST for availing benefit schemes like free cycle and uniform, besides free electricity to farmers having up to five acres.
Shahi also referred to a similar decision by the Supreme Court in the case of government of Jagdambika Pal in Uttar Pradesh.
JD(U), RJD, Congress, CPI and one Independent supporting Nitish Kumar have already submitted a memorandum to Governor Keshari Nath Tripathi to stop Manjhi government from taking big decisions which they said would cost the state exchequer an additional Rs 50,000 crore.