Domestic violence experts are furious with a "woefully deficient" consultation period on radical changes to Australia's family court system.
Angela Lynch, from Women's Legal Service Queensland, says it is frightening the merger plans are being put forward without speaking to people dealing with victims of violence.
"These are radical, extreme and potentially dangerous changes to our family law system," Ms Lynch said on Monday.
"The proposed model moves from a specialist approach to adopting a generalist court model, and yet the government appears determined not to listen to experts."
Ms Lynch warned victims of family violence and their children would bear the brunt of the "terrible" process.
Opposition and crossbench senators are also seething the government has refused to give them more time to consult on the court reforms.
Late last week, government members overruled a majority vote of a Senate inquiry to extend a reporting date until next year.
The Family and Federal Circuit Courts are due to merge on January 1.
Shadow attorney-general Mark Dreyfus said the government's "astonishing" timetable would give interested parties just three weeks to make submissions on the nearly 200-page bill.
"Vulnerable families and children in the court system need change - but they need change that is done properly and done right," he said.
Law Council of Australia president Morry Bailes said the three-week time frame was insufficient and extremely worrying.
He wants the reporting deadline extended to April 2019.
"We owe it to the people caught up in the family law system not to give the most significant court changes since 1975 a mere cursory glance, or a simple tick-and-flick," Mr Bailes said.
Attorney-General Christian Porter said most of the bill duplicated existing provisions, and just one quarter of clauses were new or substantive changes.
Mr Porter said there was no reason the consultation period needed to stretch for six months, given the issue had been the subject of five separate reviews available to the committee.
"The actual reforms are not overly complicated and we will work with the Senate committee members to ensure they have all the information they need to get the job done," he told AAP.
Merger plans introduced to parliament last week are aimed at speeding up complex trials, cutting the backlog of unresolved cases, and reducing prolonged and acrimonious family disputes.
The new Federal Circuit and Family Court of Australia would be split into two divisions under the leadership of one chief justice.
With 90 per cent of the Federal Circuit Court's caseload consisting of family law matters, the court would provide a single entry point.
Crossbencher Rex Patrick has warned the "untidy game of push and shove" between the Liberal-controlled committee and senators could be setting Prime Minister Scott Morrison up for his first legislative failure.
