Benitez is hugely popular with the fans at St James' Park, but Ashley has consistently refused to back him in the transfer market despite promising that he would have available 'every penny the club generates'.
Ashley has previously admitted in court that he deliberately mislead and lied to the fans of Newcastle and the general public.
"I was talking with Steve Nixon today, the head of recruitment, and not talking about January," Benitez said.
"I don't know my budget but it is not a problem. I'm used to working without big money in all my teams - not at Liverpool, Chelsea or even Real Madrid were we spending big money.
We were still achieving something. I have confidence we will do it with this group of people, with this staff and these players.
"We can achieve what we want to achieve, which at the moment is to stay up."