Fun Police will focus on the employees of Brightsea Council's Health and Safety department, and has been written by The Russell Brand Show co-host Matt Morgan.
Flight of the Conchords star Darby will play eccentric office boss Leslie, who takes charge when the previous boss suffers an accident in the workplace.
Cemetery Junction's Jack Doolan, Tracy Beaker actor Clive Rowe, Him & Her star Kerry Howard and Not Going Out's Katy Wix will star alongside Reeves and Darby.
Man Stroke Woman writer Dan Hine will serve as producer on Fun Police, while The Office's Ash Atalla will executive produce. The IT Crowd director Richard Boden will helm the series.
The project is part of the third season of Channel 4's Comedy Showcases, which previously spawned full series of The Kevin Bishop Show, Campus and The Increasingly Poor Decisions of Todd Margaret.
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Watch a clip of Rhys Darby on HBO's Flight of the Conchords below: