The Argentine defender was expected to leave the club this month after expressing a desire to return to South America for personal reasons, but following talks with the North-East outfit, Coloccini has opted to stay put until the end of the season.
"The last few weeks there has been a lot of talk about my future," Coloccini told the club's official website. "But I am staying here. And of course I will give 100% like I always do.
"I have been here five years and Newcastle has given me a lot and done a lot for me. I have to be true to the club. I will give 100%. I love football and once I am on the pitch it is different. The problems I have are outside the pitch.
"I heard in the city and around the club that the fans think I have my head elsewhere thinking about other things, or that I am not the same player as last season. The fans have to know and be sure that when I am the field I give 100%. I am the captain of the team and I take the responsibility."
The 31-year-old has been at St James's Park since 2008.