* Pre-trial rules that would erode the right to silence for the accused, because they would have to disclose all aspects of the case in dispute to the prosecution before a trial. Failure to do so would mean a judge or jury could view the accused as more likely to be guilty. At present a defence can stay silent and the burden of proof is entirely on the prosecution.
* Changing the jury trial threshold so defendants could elect trial by jury only if charged with an offence carrying a maximum sentence of at least three years' jail. The threshold is now three months. Changing this would require amending the Bill of Rights Act.
It is understood that Justice Minister Simon Power was yesterday negotiating with the Maori and Act parties. Neither the Maori Party nor Act would comment last night.
The bill was reported back from the select committee in July, with Labour and the Green Parties opposing it.
Last night Labour's justice spokesman Charles Chauvel said the party could support the bill, if some aspects of the bill were removed.
"Labour thinks that the bill is by no means all bad. There were the four major constitutional points that we referred to in our minority report, and we don't regard those as negotiable."
In addition to the pre-trial rules and the trial-by-jury threshold, Labour opposed widening the scope of allowing trials to proceed in the absence of defendants, and the provision to fine the accused or their lawyer for failing to follow correct procedure.
"If as a result of what appears to be the Government losing the numbers to pass the bill, if Simon Power was prepared to do what he should have done in the beginning and remove those four offensive provisions, we could look at supporting the rest of the bill," Mr Chauvel said.
"Those were our big concerns for which there were a lot of adverse submissions, and from what I understand they are likely to be the basis on which other parties have withdrawn their support."
Green Party justice spokesman Kennedy Graham referred to his speech at the bill's first reading, in which he raised concerns about similar aspects of the bill, including the right for a defendant to be present at trial, and the pre-trial regime. But he supported the objective of the bill.
A spokesman for Mr Power said: "Negotiations are continuing, as would normally be the case when a bill comes back from select committee."