US tech giant IBM is coming under increased pressure to justify its role in the shambolic failure of the 2016 census, as legal experts questioned whether the federal government will have the stomach to back up its tough talking with a legal battle for compensation.

Prime Minister Malcolm Turnbull made it clear in a media conference and numerous interviews on Thursday morning that he believed IBM had bungled its role as the census' chief technology provider, but questions remain about how likely it is that an inquiry into the debacle will lead to legal challenges.