In the Assembly, today Mrs Foster said: "The EU needs to stop using Northern Ireland to get their own way.
"We are not the plaything of the European Union and it causes great difficulties here in Northern Ireland when people use Northern Ireland in that fashion."
Mrs Foster urged the EU/UK Joint Committee to make progress, expressing surprise there is still a standoff around the issue of goods being imported to Northern Ireland from Britain.
"I am amazed that that issue has not yet been solved because it's a very straightforward issue," she said.
Mrs Foster added: "That should not be used as a bargaining chip, but instead it should be dealt with as quickly as possible."
On the UK Internal Market Bill, the First Minister said: "The GB market is our largest market so it is important that we have unfettered access into the market and that is what I hope this bill will achieve."
She added: "Sometimes when I listen to EU negotiators and they talk about peace in Northern Ireland, it is apparently only if we have free access north/south, there's very little conversations about access east/west, and of course we do need that in a more fundamental way.
"I can understand why the north/south issue was such a big issue, and I recognise that, but there were other ways to deal with that.
"Those other ways were pooh-poohed and not listened to, and unfortunately we now find ourselves in this situation.
"So there needs to be an acknowledgement that east/west - the integrity of the United Kingdom - needs to be protected as much as having to deal with the north/south trade."