LONDON (REUTERS) - British Prime Minister Boris Johnson's government reached a deal on Wednesday (Sept 16) to avert a rebellion in his own party, giving parliament a say over the use of post-Brexit powers within its proposed Internal Market Bill that break international law.

The bill is aimed at ensuring Britain's four constituent nations can trade freely with each other after fully leaving the European Union, but the government says that requires overriding part of the withdrawal treaty it signed with Brussels.

Although the bill passed its first test in parliament on Monday (Sept 14), it has been heavily criticised by some within Johnson's party.

A plan to give lawmakers a veto on using the powers had been put forward by a Conservative member of parliament, Bob Neill.

The government and the rebels in a joint statement said they had agreed a deal where parliament must vote for a motion before the powers can be used by a minister.

"There is near-unanimous agreement that the government must be able to use these powers as a final resort, that there must be legal certainty, and that no further amendments are required on these powers," Downing Street, Neill and another lawmaker Damian Green said in a joint statement.

Although Johnson struck a deal to appease rebels in his own party, it is unlikely to soften the EU's attitude.

Brussels wants Johnson to scrap the bill, saying it could sink talks on future trade arrangements before Britain leaves the EU's single market, which it has remained part of during a status quo transition expiring at the end of this year.

Johnson has refused.

The deal has not dispelled all domestic criticism of Johnson's plan either, and his top Scottish law officer resigned on Wednesday in opposition.