The duo have each penned two-year deals with the Jets, with boss Scott Miller delighted to have attained the services of both players.
"Mateo will provide composure and leadership in our midfield, and we see it as a major coup for the club that we have been able to attain his services," Miller told Newcastle's official website.
"Labinot is a noted A-League performer and someone who offers us flexibility in our attacking systems."
Poljak in particular played a key role in the Wanderers' Asian Champions League triumph in 2014 while Haliti returns to the club for whom he made over 60 A-League appearances between 2009 and 2012 and close to 30 outings in his first stint which began back in 2005.
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