The Treasury's warning should be heeded more generally.
Parliament has been sitting under urgency in this, its final week of the year, to introduce a number of bills in haste — for no better reason than they are policies it promised in its first 100 days.
Why has 100 days become so important? A newspaper should perhaps not be asking this question since 100-day plans are as much a focus of the media as incoming governments, but they are supposed to be just a guide to a new government's priorities, not a deadline ministers must meet at all costs.
For the sake of good law, let it be agreed it is worth waiting more than 100 days for well researched and properly considered decisions.
Rushed legislation is almost certain to have perverse results and have to be revised by Parliament before long. It is quicker and less costly to get it right the first time, no matter how long it takes.
It would have been much better if the ban on foreign buyers had been reconsidered. The ban was proposed by the Labour Party years ago, when prices were still rocketing further out reach of average income earners.
House prices have been flat or falling for the past 18 months and there is no sign they are about to take off again.
Likewise in tertiary education. Universities have expressed concern that abolishing fees will have an unknown impact on the number and type of additional students applying for courses next year, and it would have been useful for the policy to have been researched first.
This week has also seen the introduction of legislation to allow the use of cannabis for medicinal purposes and changes to employment law to regulate pay and conditions across industries are in prospect. These have serious social and economic implications and should not be rushed.
Fortunately, some of the 100-day projects are merely to "set up" (inquiries into tax, mental health, historic residential care) or "begin work on" (a house building programme).
These should meet the 100-day milestone in February without putting themselves on an unwise course with premature decisions. But nothing on the agenda should be subjected to that risk.
On every item, the Government should take its time and get it right.