Former Inter Milan and Real Madrid striker Ronaldo has suggested that the current Brazil international side is the worst of "the past few years".
The 39-year-old - who scored 62 goals in 98 international appearances - believes that Dunga's current team is weaker than other recent sides, and that they could struggle to qualify for World Cup 2018.
Speaking to Brazilian television station SportTV, Ronaldo said: "Of teams from the past few years, this side provides the least hope for our fans.
"We're going to find it difficult to qualify for the 2018 World Cup, not because of the opponents we face but because of us.
"In the last few tournaments we have played in, Brazil were inferior to their opponents."
Ronaldo was part of the Brazil side that won the tournament in 2002, where he scored eight goals to win the Golden Shoe.