Kelly was found dead with a slashed wrist in July after being revealed as the source, prompting the government to launch an inquiry into his death headed by Lord Hutton.
The committee also criticised embattled Defence Secretary Geoff Hoon, who has been targeted by opponents as a fall guy for the government's troubles over the case it made for war in Iraq.
Hoon is widely expected to be the first ministerial casualty of the Iraq crisis: the worst of Blair's six-year premiership and one that has sent his public ratings tumbling.
Hoon's Ministry of Defence was "unhelpful and potentially misleading" about its concerns over the government's dossier on Iraq's banned weapons, the committee said in a report.
"We regard the initial failure by the MoD to disclose that some staff had put their concerns in writing to their line managers as unhelpful and potentially misleading," the cross-party committee said, fingering Hoon personally.
"We are disturbed that after the first evidence session ...the defence secretary decided against giving instructions for a letter to be written to us outlining the concerns."
The committee's investigation ran in parallel to a judicial inquiry into the suicide of weapons expert David Kelly who was exposed as the source for claims that the government exaggerated the threat from Iraq.
Judge Lord Hutton's inquiry has already revealed that at least two Defence Intelligence staff were unhappy with warnings in the dossier. The committee said intelligence chiefs did not know for sure what weapons Iraq had made or in what quantities.
"This uncertainty should have been highlighted to give a balanced view of Saddam (Hussein's) chemical and biological capacity," it said.
- REUTERS
Hutton inquiry website
British Parliament Foreign Affairs Committee transcript:
Evidence of Dr David Kelly
Key players in the 'sexed-up dossier' affair
Herald Feature: Iraq
Iraq links and resources