The invention relates in a one aspect to a method or apparatus for measuring flow properties of a multiphase fluid stream flowing in a pipeline comprising means for sampling, with a sampling probe, a portion of the fluid stream; for measuring a differential pressure between a first pressure of the fluid stream in the pipeline and a second pressure of the portion of the fluid stream in the sampling probe; for controlling flow rate of the sampled portion, wherein the flow rate of the sampled portion is controlled to provide for nullification of the differential pressure in order to obtain substantially isokinetic sampling of the fluid stream; for measuring properties of the portion of the fluid stream; and for processing the measured properties to determine the flow properties of the multiphase fluid stream flowing in the pipeline, wherein the above elements do not require- or are performed without the determination of the density of fluid in the fluid stream through nuclear radiation methods.