Legislation to disapply parts of the Northern Ireland protocol will be published next week, but senior government sources acknowledge it is going to be a “difficult” process to get it through parliament. The new laws are aimed at unilaterally changing parts of the protocol to make trade easier between Northern Ireland and the rest of the UK, but critics say overriding the post-Brexit treaty could contravene international law. The bill will be published on Monday along with a legal document that the government hopes will address some concerns. A senior government source denied that the legislation had been substantially changed as a result of lobbying by the hardline Eurosceptic right of the Tory party after a meeting between Liz Truss, the foreign secretary, and Bill Cash, one of the European Research Group of backbenchers. The source said there “shouldn’t be any big surprises”, adding that “we engage all the time with MPs across the party” and the ERG had “not had particularly privileged access”. They said the legislation would include “practical reasonable solutions to fix parts of the protocol, including to fix bits that don’t work, including east-west trade, governance, dual regulation and state aid.” However, the source said no vote for second reading of the bill had yet been scheduled, and they acknowledged “how difficult this is going to be”, with the legislation expected to be harder to get through the Lords than the Commons. Another senior government source said it was difficult to see how ministers would be able to publish a bill that satisfies both the Eurosceptic right and the one nation wing of the Conservative party. Keir Starmer has said a Labour government would repeal the legislation to override the Northern Ireland protocol if it passes. The Labour leader said his party would vote against the legislation, and if he gained power he would scrap it, while acknowledging there were “issues” with the protocol, which is blamed for slow movement of goods between Northern Ireland and the rest of the UK since Brexit. “We would scrap the legislation and I think there has been an impasse in the negotiations because we haven’t seen the high levels of trust that we need for negotiations like this, not least from our prime minister,” he said in Belfast. “But also we need give and take on both sides. The EU, as well as the UK … to be flexible about the approach. I do not think that the remaining issues of the protocol cannot be resolved with a different approach, with that high level of trust, with an honest broker prime minister getting people around the table and negotiating what needs to be negotiated.” Starmer’s trip to the island of Ireland involved meetings with Irish government ministers in Dublin. The bill has been the subject of fierce lobbying by arch-Eurosceptics in recent days who want the protocol dropped entirely. Boris Johnson and other senior ministers have been put under pressure by ERG MPs to put forward legislation intending to take primacy over the protocol and removing the role of the European court of justice. The EU has hardened against the UK’s actions in recent weeks, with the Irish taoiseach warning that ditching the protocol would be a “historic low point” in relations, citing the Ukraine war as a reason why international law must be respected. Micheál Martin said in an address to the European parliament this week that breaching the protocol would make the world less safe and that Johnson must not “treat lightly” peace on the island of Ireland. Conor Burns, a minister for Northern Ireland and ally of Johnson, said the UK government was “recalibrating, not tearing up” the protocol. The legislation is also opposed by a chunk of Johnson’s own MPs on the one nation wing, with the former Treasury minister Jesse Norman warning on Monday it may be illegal.