The former Edinburgh Gunners chief took charge of his first official training session on Monday in preparation for the visit of Argentina, Samoa and the All Blacks next month.
Hadden took over officially from the sacked Matt Williams last month after guiding the Scots to successive wins against the Barbarians and Romania in the summer.
But, after Scotland won just three Tests from 17 attempts under Williams, the new head coach is looking to close the gap on the major names in the game.
However, he warns the threat of Argentina and Samoa at Murrayfield - before the visit of New Zealand - must not be under-estimated.
Hadden said: "We have some great challenges ahead, never mind the All Blacks.
"Argentina are very much a growing power and a very under-rated international force. They have a fantastic junior set-up.
"I have been there a couple of times myself and I know how good they are.
"There are a number of sides working incredibly hard to challenge the big five of New Zealand, South Africa, Australia, England and France and that is one of our aims.
"Samoa are another tough test. I expect them to be able to put out a first-class side.
"They are a totally different challenge to Argentina and New Zealand and that's the excitement of international rugby."