The Spaniard was in charge of the Reds for seven years from 2004 and guided them to their fifth Champions League title in his debut season.
After spells at Inter Milan, Chelsea, Napoli and Real Madrid, Benitez was brought in to save Newcastle from relegation in March last year.
Newcastle will be hosting Liverpool in the Premier League on Sunday and when asked if he had ever considered going back, the 57-year-old refused to rule it out.
“I haven’t had too many chances to go back. But that is football, you never know,” he said.
Have I come close? The job is quite difficult. I have been in Italy or Madrid or moving around. It has to be the right time. When you have problems and are available, they might be doing well.
“I am getting older but for a manager still a young manager.
“I don’t want to say (I will go back). I am really pleased here. I am happy here. And I wish Jurgen Klopp a lot of success.
Benitez admitted playing against his former side will be a special and emotional experience.
"It's a special game for me. It will be emotional, because I spent so many years there, and have so many good memories. My family still live in Liverpool, so it is my home," Benitez told Newcastle's website.
"I have a lot of positive, very good relationships with Liverpool fans, (including) the families connected to Hillsborough. There are a lot of connections, and it will be very emotional."
Nostalgia aside, Benitez said he is focused on ensuring his team get all three points.