Also, even in the US the tax savings aren't a good reason to get a longer duration and a larger loan. There are other reasons people might decide a longer duration is best for them, but paying an extra $1 to save 25 cents in taxes isn't one of them. Also if you pay less than 20% down you need to pay mortgage insurance, which is like an extra fee that you don't get back when you sell the house.
Example - lets say you're in the 25% tax bracket and you're deciding between a 30 and a 15 year mortgage. In both examples you're planning to buy a $250,000 house. Using today's rates and this calculator, assuming you can deduct all the interest every year at 25%:
$200,000 loan for 15 years at 3.625% - pay $59,662 in interest over the life of the loan. Deducting about $15k you'll pay $45k total.
$200,000 loan for 30 years at 4.375% - pay $159,698 in interest over the life of the loan. You can deduct more, $40k, but you still pay almost $120k in interest! That's $75k more
Don't let the tax tail wag the financial decision dog.