The CFMEU has had its bid to stall a court battle against building materials group Boral rejected in the High Court.
Boral is seeking damages from the Construction Forestry Mining and Energy Union (CFMEU) in the Victorian Supreme Court, alleging intimidation and a conspiracy by the union hit its profits.
High Court Justice Kenneth Hayne on Friday dismissed the union's application to stay the Supreme Court trial, set for April 13.
Justice Hayne said he wasn't aware of the state of the Supreme Court's lists and didn't know how long Boral could be forced to wait for its day in court if he vacated the date.
He said he was therefore in no position to order a stay.
"This court should not grant any stay of the CFMEU without knowing first that an application has been made in the Supreme Court and its outcome," Justice Hayne said on Friday.
He also noted both parties were large and well resourced.
"Neither side can be treated as being unused to litigation," he said.
The CFMEU had hoped to win the stay application while it considers pursuing separate High Court action.
Justice Hayne said his ruling should not prejudice any future application before the same court based on new material.