Newcastle were the only Premier League side not to make a permanent senior signing in the close-season, with the loan arrival of Loic Remy the only addition to Alan Pardew's squad.
However, ahead of the sides' meeting at Goodison Park on Monday, Martinez is of the opinion that Pardew's Newcastle side have a togetherness and balance.
"There has been a lot of talk that they lacked activity in the transfer window but I don't see it as a negative," he said.
"The (Newcastle) squad is well balanced. I do see a very stable squad and if you take away the (Manchester) City game this squad is as strong as you'll find.
"They have experience and attacking threat."
Everton are the only side yet to taste defeat in the Premier League this season, with their last domestic outing yielding a 1-0 win over title hopefuls Chelsea.
However, they were beaten 2-1 in the League Cup by Fulham on Tuesday and Martinez is keen to ensure his side bounce back against Newcastle
"We're desperate to get on the pitch and get back to the feeling we experienced at Goodison against Chelsea," he continued.
"We enjoy the feeling of playing with the support you have from our fans. They really make the difference. The chemistry is unique."
Everton will be without defender Antolin Alcaraz for between three and four weeks, having suffered a setback in training, while Steven Pienaar remains a doubt with a knee injury.
However, Martinez could welcome back Leon Osman and Arouna Kone into his side, saying "it wouldn't surprise me if they are available".
