Labour MPs are hoping to hijack plans to cut back on jury trials in England and Wales by proposing specialist courts for sexual offences with fixed dates for trial.

While those behind the amendment want to block the wider plan to stop thousands of cases being potentially eligible for jury trials, a measure ministers insist is needed to cut court backlogs, they say the specialist courts alone could still solve much of the problem.

The government is braced for possible rebellions when the courts and tribunals bill returns to the Commons after Easter for its committee and report stages, when amendments are considered and, in some cases, voted on.

Backers of the new amendments said they believed 90 or more Labour MPs could either vote against the government or abstain if their demands were not met.

In a campaign coordinated between different factions of backbenchers, the first amendment would strike down the bill’s central aim: to remove the right of defendants in “either way” cases, where they can opt for a magistrate or jury trial, to pick the latter.

Even though judges can impose heavier sentences than magistrates, ministers say more people are opting for a jury trial in the hope that the prolonged wait for the case to be heard could lead to the charges being dropped as victims and witnesses give up.

The second amendment, tabled by Charlotte Nichols and Stella Creasy, would create specialist courts for cases involving sexual offending or domestic abuse, which would have time limits for cases to be prepared and a fixed trial date.

While sexual offences such as rape will still be tried by juries even if the bill is passed, ministers have consistently argued that one of the main reasons for the proposed changes is to speed up the progress of sexual cases through crown courts.

However, Nichols has argued that sexual offences are being “weaponised” by the government to force through the bill. Last month, the Warrington North MP told the Commons how she had waited more than 1,000 days for the trial of a man accused of raping her, but opposed the bill nonetheless.

Nichols argues that given Labour promised in its manifesto to “fast-track rape cases” with specialist courts at every crown court in England and Wales, the amendment in her name would be the correct way to deal with the backlog.

“For me, the specialist rape courts would get rid of the need for the changes to jury trials,” Nichols said. “But it would be a significant enough win for victims that if the wider bill did still pass, we would have done enough that I could sleep at night.”

Some rebels behind the amendments have held talks with David Lammy, the justice secretary, and Sarah Sackman, the courts minister, who are understood to have not entirely ruled out some movement from the government.

Nichols said that if there was no movement, she and a large number of Labour MPs could potentially defeat the government, given there were 10 Labour votes against and 90 abstentions at the second reading of the bill in March.

“If ministers show no willingness to address people’s concerns, then you could end up with a lot of people who abstained at second reading as a show of good faith, now voting it down, and some who voted in favour deciding to abstain. The ball is very much in the government’s court now.”