He was speaking after Secretary of State Brandon Lewis claimed the legislation was within the law.
The legislation is set to be published for the first time on Monday.
Said the Foyle MP Mr Eastwood: “When I challenged Boris Johnson to commit to upholding international law in the House of Commons this week he was unable to give me a straight answer.
“We know that his own advisers believe the Protocol legislation will breach the agreement with the EU and the attempt by Brandon Lewis to suggest otherwise is fooling nobody.
“Johnson and his government have proved time and time again that they will say and do anything that furthers their own self-interest.
“They have a casual relationship with the truth and have shown they are willing to totally disregard the law and the feelings of the people they represent as and when it suits them.
“They have no regard for people in the North or the serious harm this and their move on legacy will have on people here.
“Throughout the Brexit process this government has refused to put the needs of people in the North first and reach an agreement that will benefit both sides.
“This legislation is an extraordinary act of bad faith from a government that has proved it can’t be trusted and it will be people in the North and Britain that suffer as a result.”