The committee, chaired by the MP Andrew Dismore, comprises twelve members appointed from both the House of Commons and the House of Lords.
The committee said that technical measures, which include cutting off unlawful file-sharers, are not "sufficiently specified". It was also concerned that the bill could create "over-broad powers".
It expressed misgivings over the "three strikes rule", and how it would be applied. The rule would give Ofcom new powers to disconnect or slow down the connections of persistent net pirates.
The government has not specified whether an entire household would be cut off, even if only one member of the family has been identified as an illegal file-sharer.
The committee said that such measures breach internet users' rights and had not been "sufficiently specified to allow for an assessment of proportionality".