LONDON (AP) — Brexit will descend into chaos if lawmakers don't approve a bill designed to lay the legislative framework for the country's EU exit, Britain's minister for leaving the European Union has said.

Lawmakers are due to vote late Monday or early Tuesday on the European Union (Withdrawal) Bill, which aims to convert around 12,000 EU laws and regulations into domestic statute on the day the country leaves the bloc in March 2019.

The legislation is a key plank in the government's plans to disentangle Britain from the EU after more than four decades of membership.

Brexit Secretary David Davis said "a vote against this bill is a vote for a chaotic exit from the European Union."

"The British people did not vote for confusion and neither should Parliament," he said.

The government says the bill is needed to avoid a legislative black hole on the day Britain leaves the EU.

The bill will incorporate all EU laws into U.K. statute so they can then be kept, amended or scrapped by Britain's Parliament. The government says that will fulfil the promise of anti-EU campaigners during last year's referendum to "take back control" from Brussels to London.

Critics say the bill gives the government worrying powers, because it allows ministers to fix "deficiencies" in EU law without the parliamentary scrutiny usually needed to make or amend legislation. Such powers are often referred to as "Henry VIII powers" after the 16th-century king's bid to legislate by proclamation.

Opponents worry the Conservative government could use such powers to water down environmental standards, employment regulations or human rights protections.

Lawmakers are debating the bill Monday in the House of Commons with a vote due around midnight.

The main opposition Labor Party and smaller Liberal Democrats both say they will vote against the bill. But it will pass unless pro-EU lawmakers from the governing Conservatives rebel.

Many of them say they will vote for the bill now and try to amend it at the next stage, when it receives line-by-line scrutiny from lawmakers.

Ken Clarke, a pro-EU Conservative lawmaker, said the government would have to water down "powers that Henry VIII would have been delighted by."

"I think Parliament will be sensible to get them to write it to make sure there's not the possibility of using powers that no government's ever tried to take," he told Sky News.