David Davis has described a Leaked EU paper suggesting it could cut UK access to the single market if there was a post-Brexit row as "discourteous".
The UK Brexit secretary said it had not been "in good faith" to publish it.
He also said every economic forecast about Brexit had been "proven wrong so far".
Official forecasts out earlier suggested it would mean a slowdown in growth across the UK.
Mr Davis was speaking after the prime minister chaired meetings of the Brexit cabinet committee, aimed at sketching out what the UK wanted its future relationship with the EU to look like.
He said the atmosphere had been "very constructive" and there had been "lots of things resolved" but admitted there was "still progress to be made".
He described the draft section of the withdrawal agreement that leaked out on Wednesday as "hardly a legal document, it was a political document".
"What we're about, is building an implementation period which is to build a bridge to a future where we work well together," he said.
"I do not think it was in good faith to publish a document with frankly discourteous language and implying that they could arbitrarily terminate in effect the implementation period.
"That's not what the aim of this exercise is. It's not in good faith. We think it was unwise to publish that."