The United States is keen to get its big free trade agreement with Pacific countries.

Senior American officials at the Apec meeting say it should be wrapped up by the end of the year. And Prime Minister John Key, while sceptical a day earlier, now thinks it is possible. In New Zealand, employers are also champing at the bit. We need to hurry, they cry, because every day without a free trade agreement is a day of lost opportunity.

There is no such hurry and New Zealand should resist any attempt to stampede it into a deal. The Trans Pacific Partnership is too important, and potentially too dangerous, for New Zealand to rush into. There have been persistent reports that the government is prepared to soft-pedal on vital New Zealand interests in the areas of drug regulation, copyright and intellectual property. And because all the negotiations are done in secret, we cannot be sure the reports are wrong.

Mr Key says he is now eager to show the public what a good deal he has negotiated. Nobody should accept these assurances until the politicians reveal the fine print. The main concern is about Pharmac, the government's drug- buying agency that keeps drug bills down for New Zealanders.

The big American drug companies detest it and want it gone. Mr Key and his trade minister, Tim Groser, say that they will not sacrifice Pharmac. At the same time they say that everyone has to "give a little bit" in negotiations.

So the question is: How much of the Pharmac system is the government prepared to give away? We don't know and it would be absurd to accept the bland assurances of politicians that they will protect New Zealand's vital interests. There is room for genuine debate about what those interests are. And it is certain that many voters will not agree with the Government's view.

Leaks have suggested that the US will not be so crude as to insist that New Zealand close Pharmac down. Rather, it has been suggested, Pharmac will be required to give detailed public evidence for its decision and that these decisions should be open to "review". This sounds ominously as though the US wants to open up our drug policy to litigation and endless argument funded by super-wealthy foreign corporations.

We won't know until the details of the deal are finally announced. But by then it may be too late. Mr Key says the deal will go before Parliament. But that doesn't mean much, as long as his usually reliable little helpers support him. If so, the Government would be able to pass into law a free trade deal that is profoundly harmful.

As the Nobel Prize-winning economist Joseph Stiglitz once observed, most "free trade" deals are nothing of the kind. They are, rather, patchwork deals whose gaps reflect the strength and determination of the most powerful and wealthy interests.

New Zealand's free trade agreement with China did not face insuperable obstacles, mainly because the two countries have largely complementary economies. The US and New Zealand do not. We face "negotiations" with the monstrously powerful American agriculture, drug and business lobbies. They don't surrender easily.