The Abbott government is set to dissolve a Senate committee scrutinising the National Broadband Network and replace it with a new committee dominated by Coalition members.

A move by Liberal Senator Cory Bernardi to introduce two motions into the Senate on Wednesday has been delayed until Thursday.

Senator Stephen Conroy (centre) and other Select Committee members at one of many hearings on the NBN in 2013. Credit:Alex Ellinghausen

The first motion would abolish the current Senate Select Committee on the NBN and the second would establish a new Joint Select Committee to monitor the NBN rollout and the company's financial and operational performance. The motions are expected to pass with the support of the Palmer United Party senators.