The 28-year-old has been an ever-present for the Navarra-based outfit this term, and has been a key figure in their excellent start to the campaign.
Osasuna currently sit fourth in La Primera, having taken three wins and two draws from their opening six league fixtures, and Punal expressed his delight at extending his stay at Estadio El Sadar.
"It's recognition from the club for the work I have given to the team, and it gives you a tranquillity on a personal level," stated Punal.
"My idea from the start was to continue here, and only if Osasuna had not shown an interest in keeping me would I have considered other options.
"Hopefully I could extend the deal again for two or three years and end my career here."
