The prime minister has held “frank” conversations with the DUP about the Northern Ireland Protocol during a visit to the region, while he was snubbed by Sinn Fein.
Mrs Foster urged Mr Johnson to “stand up for Northern Ireland” and scrap the “intolerable” protocol, which governs Irish Sea trade in the wake of Brexit.
The first minister said the PM had been in “listening mode” and “alive to the issues”.
“Not a single unionist party in Northern Ireland supports this unworkable protocol,” she said.
“Rather than protect the Belfast Agreement and its successor agreements, the protocol has created societal division and economic harm.
“Whilst grace periods have been extended unilaterally, we need a permanent solution so business can plan and the integrity of the United Kingdom internal market can be restored.”
Mrs Foster told Mr Johnson that a school in Fermanagh has been unable to order trees from England because of bureaucracy surrounding the transport of soil.
In an effort to ensure there is no hard border on the island of Ireland, the protocol allows Northern Ireland to remain under some EU rules.
But this means there has to be customs declarations on goods entering Northern Ireland from Great Britain, including checks on some products.
This has led to disruption to trade, with firms struggling with new processes and administrations.
Unionists are against the arrangement, arguing that it undermines Northern Ireland’s place in the UK internal market.
Nationalists, meanwhile, recognise that there are teething problems but argue these can be fixed without scrapping the protocol altogether.
The deputy first minister, Sinn Fein’s Michelle O’Neill, refused to welcome the PM to Belfast.
It came after a request for a political meeting with her and Sinn Fein leader Mary Lou McDonald was rejected.
Ms O’Neill said: “Mary Lou McDonald and myself have a long-standing request to meet with the British prime minister to discuss a number of commitments which he and his government have reneged on in the New Decade New Approach over this past year, and also his reckless and partisan approach to the Irish Protocol. He did not facilitate the meeting.
“I have no plans to meet with him today.”
Sinn Fein MP John Finucane said the party was refusing to engage with what he called a “day out for unionism” after Downing Street rejected a request for a “professional, grown-up engagement” covering issues like the protocol.
“We’re not in the business of engaging in a fairly superficial PR stunt, which is what the British prime minister invited us to do today,” the North Belfast representative said.
“We have made the request to meet with him. I think it’s insulting to the 770,000 people on this island who vote for us that he feels it appropriate to ignore and refuse that meeting.”
The PM’s spokesman said: “Michelle O’Neill was invited to join the PM on the visit.”