Other Asian, Australian and South Pacific Frequent Flyer Programs - Australia - flight prices @ new year period

I AM LOOKING FOR ADVISE ON PRICES OF FLIGHTS

we are visiting sydney - whitsundays - melbourne in december/january

Sydney to hamilton island - 3rd JANUARY - 186 AUD JETSTAR direct flight including 10kg hand luggage and 20kg hold luggage

hamilton island to melbourne - 7th JANUARY - 216 AUD JETSTAR direct flight including 10kg hand luggage and 20kg hold luggage

Do u think the flight prices will go up, should we go ahead and book them maybe?

source - webjet and double checked on jetstar website

This will be a high travel period in Australia.