"May God help you -- it's a very difficult mission," Prime Minister Youssef Chahed said at the launch of the unit, with their new uniforms and GPS-equipped pick-ups.
The North African country's rubbish woes have worsened because municipalities are not dealing with the problem in advance of local elections slated for December.
There is also a lack of equipment, treatment centres and landfills, Environment Minister Riadh Mouakher said.
"Even municipalities themselves sometimes dump their waste in public spaces," he told reporters.
But he also pinpointed a lack of awareness among the general public.
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For a month, the environment police will be responsible for raising that awareness, Mouakher said.
After that, from mid-July, throwing trash outside dumpsters or burning waste will incur fines of between 40 and 60 dinars (14.5 and 21 euros).
And if an offence is deemed to be damaging to the public health, a prison term can be or higher fines of between 300 and 1,000 dinars can be imposed.
Initially, the new force will deploy 163 officers in 34 municipalities across greater Tunis.
In mid-July, an additional 136 officers will patrol another 40 municipalities across the country.
The "green police" will come under the authority of municipalities -- but will also be monitored by the environment ministry.
In another measure taken in March this year aimed at ending "visual pollution", Tunisia banned plastic bags from supermarkets.