Before you take out a payment holiday, read your bank contract carefully - it should explain exactly how they work in your situation. Different programs vary: sometimes interest is just deferred until later, sometimes it gets capitalized (added to the loan principal), and sometimes the loan term itself can change. This isn't a minor detail - the difference in how much extra you'll pay can be significant.
The main catch is that after the holiday, your debt won't shrink; it might even grow because interest has been piling up. Then you'll have to pay back more money, and probably in a compressed timeframe - either that or you'll be paying for longer than you planned. Plus, banks often require documents proving you're in financial trouble, otherwise they'll reject your application. This can show up on your credit history as a sign of difficulties, even though the payment holiday itself might not appear on it.
Practical advice: if you do decide to take a payment holiday, don't just sit around. Use that period to pay down at least part of the principal (the original loan amount) if you can. Then the base for calculating interest will be smaller, and the extra amount you'll pay won't be so harsh. Or actually, consider whether you could save up the missing amount and settle early instead of resorting to a holiday - sometimes that works out better.