McLaren cruised to an easy one-two a season ago as Fernando Alonso edged out Hamilton, with Ferrari left trailing in their wake. Felipe Massa was almost 70 seconds adrift in third, while Raikkonen was humiliatingly lapped following a poor qualifying performance.
"Obviously we struggled last year in Monaco, but I feel Ferrari has really improved in areas where we were weak last year," said Raikkonen.
The Finn ultimately finished eighth, claiming a crucial point that at the end of the season was all that separated him from both Hamilton and Alonso as he was crowned world champion.
Heading into Sunday's race around Monte Carlo, Raikkonen holds a seven-point cushion over Hamilton and Ferrari team-mate Massa.
Although McLaren are again expected to be strong this year, the 28-year-old is convinced they will not have it all their own way.
"Last week we had a test at Paul Ricard, and it went very well," assessed Raikkonen.
"We tried a few new things and improved the set-up, and I feel the car is stronger at this type of track compared to last year. That I know.
"It's difficult to say how it will go in the end. All I can say is I know we will be very competitive, but there's also McLaren and BMW.
"Having said that, Monaco can always be good for a surprise. It's the most open of all the races this year."