Newcastle secured their promotion back to the Premier League at the first time of asking last night thanks to a 4-1 win over Preston at St James’ Park.
And Shearer, Newcastle’s record goalscorer, reckons Benitez will now demand a huge budget to spend in the summer to take the club to the next level.
Benitez was left frustrated after Newcastle failed to sign a number of his top targets during the January window.
"Rafael Benitez is a huge figure at the club and he loves the place. He loves the passion of the fans,” Shearer told BBC Radio 5Live.
“He's very experienced and he's done the job he set out to do. I'm sure he'll demand that the team has to be improved and he'll demand a few quid to do that now.
“You can't stand still now. I'm sure Rafael will ask for funds to massively improve the team.
"People will realise that the team will need improving if they want to get into the top half of the Premier League.
"[The Championship] is a tough league to get out of and we've seen that the standard in that league is not great at times.
“You've got to be dogged and determined and the players have shown that for the vast majority of the season."