If the United States Congress does not pass "fast-track" authority for the Trans Pacific Partnership (TPP) within the next few weeks it will stall until 2018 at the earliest, says Trade Negotiations Minister Tim Groser.
But he said he was not versed enough in the complexities of US Congress procedures to know what the odds are of it getting through.
"You'd have to be a Trevor Mallard on standing orders to actually make an informed judgment on it.
"But my view is this has got to be done in the next few weeks or we won't get to look at this again until 2018, which is post the New Zealand  election."
Mr Groser was in contact with US Trade Representative (USTR) Mike Froman following the failure early on Saturday for Congress to pass the Trade Adjustment Assistance bill, an essential companion bill to the Trade Promotion Authority (or fast-track bill) which would expedite a conclusion to the TPP talks.
Mr Froman was working full-time to try to sort it out because the whole TPP was on the line.
Mr Groser said the fact that the US Congress did not have a whipping system - in which party representatives almost always vote along party lines - led to unusual trade-offs.
"When you don't have a whipping system in a Parliament, you get votes by putting packages of compromises together, sometimes totally unrelated to the subject matter. So that is what is going on inside Washington."
The TPP has been the top trade deal for President Obama and Prime Minister John Key since they were both first elected in late 2008.
The Democrat minority leader in the House of Representatives, Nancy Pelosi, had been neutral on the bill but voted against it and was now talking about linking it to highways.
Mr Groser believed some Democrats had voted against the assistance package to give themselves leverage for their own parochial packages, but he said it would be a mistake to assume that that was just a tactic and it would be sorted out.
The TAA bill was defeated 302 votes to 126 and it requires 217 votes to pass, despite a rare trip by Mr Obama to the Hill to plead with Democrats to support the bill.
Congress sits for two more weeks before a week-long recess, then for four weeks before a five-week recess in August.
Beyond then there is not considered enough time to conclude the TPP and draft and pass the related legislation this year.
Mr Groser said unless the Congress sorted it out within weeks it would "over Rover for a number of years".
He said the deal could not be concluded without being fast-tracked and nothing could possibly happen until after the presidential election in November 2016. The president would not take office until January 2017; the USTR would have to be appointed then confirmed by Congress; then the USTR would have to appoint deputies; and then they would undertake a review of their policies.
"The idea that this could start before 2018 is in my view naive."