The invention relates to a wet gas compression system comprising a compact flow conditioner (21), intended to be placed below sea level in close vicinity to a well head or on a dry installation, said flow conditioner (21) being intended to receive a multi-phase flow through a supply pipe (11) from a sub sea well for further transport of such hydrocarbons to a multi-phase receiving plant, and where preferably avoid sand accumulation or remove as much sand as possible from the multi-phase flow, the gas (G) and the liquid (L) being separated in the flow conditioner (21) whereupon the separated gas (G) and liquid (L) are re-assembled and enters a multi-phase meter (46) prior to boosting by means of a compressor (22). In the combined multi-phase pump and compressor unit (22), as an integrated unit, comprises a combined multi-phase pump and compressor unit (22) functioning on the centrifugal principle, used for trans-porting liquid and gas from a flow conditioner (21) to a remote multi-phase receiving plant.