The City hierarchy are concerned about the impending Financial Fair Play Regulations (FFP) that are being introduced to cap spending by UEFA.
However, according to the Sunday Mirror Sport, the Italian manager wanted to bring in a striker and defender as well as De Rossi to help with the squad depth. This has resulted in tension within the club as City look to win their first Premier League title.
"Mancini is unhappy that the club are saying they can't, or won't, back him in the market this month," a City insider said.
"He understands that FFP is already having an impact,
"But he feels that after investing so many resources to get to the top of the league, the challenge could be ¬undermined by the reluctance to bring in one or two more players."
Mancini has received £230m over the past two years to spend on players from City's owners.