Commons committees charged with scrutinising government policy were sometimes "frustrated" by a lack of co-operation, a report has said.

The criticism was made in the annual report for 2004 of the influential House of Commons liaison committee, published on Tuesday.

The committee - which brings together the chairmen of the 34 cross-party Commons select committees set up to scrutinise government activities and oversee the administration of the House - warned that it would "test" assurances given by Tony Blair that the situation would improve.

Members said the government was failing to give committees adequate access to official information or sufficient opportunity to grill ministers.