The comments came from Inger Stojberg, immigration and integration minister who is a member of the centre-right Liberal Party.
Ramadan, one of the five pillars of Islam where Muslims shun food and water from dawn until desk, began last week.
"I want to call on Muslims to take leave from work during the month of Ramadan to avoid negative consequences for the rest of Danish society," Stojberg wrote in a column for the BT tabloid.
"I wonder if a religious order commanding observance to a 1,400-year-old pillar of Islam is compatible with the society and labour market that we have in Denmark in 2018".
She also said she feared the fasting could affect "safety and productivity," giving as an example bus drivers who have "neither had a drink nor eaten for more than 10 hours".
"This can be dangerous for all of us," she said.
Stojberg previously stoked controversy last year when she posted to Facebook a photo of her smiling and holding a cake to celebrate Denmark's 50th measure for toughening immigration laws.
One of the most draconian policies came into force in 2016, allowing police to seize valuables from refugees. The government backpedalled slightly to exempt wedding and engagement rings after the measures drew international outrage and comparisons to Nazi Germany.
In 2013, the centre-left Social Democrats removed the integration potential requirement. However, the change was shortlived after Stojberg suspended Denmark's participation in the UN refugee resettlement programme in 2016. Stojberg also attracted criticism after launching a series of adverts in Lebanese newspapers in 2015 warning would-be migrants of the difficulties of seeking asylum in Denmark.
But observers say an effective "Muslim ban" had already been in place in the northern European country for years.
In 2005, Denmark's conservative government introduced legislation requiring refugees be screened for "integration potential". Authorities did not select resettlement refugees from camps in predominately Muslim countries between 2006 and 2013.
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