It had been suggested in Italy that City were preparing a £30 million offer for Inter Milan midfielder Sneijder in an attempt to snatch the player from United's grasp.
But Mancini was adamant there will be no approach for Sneijder when asked if he was interested in the Dutch international.
"It is not true. Sneijder is an Inter player. I never speak about him," Mancini said after City's 3-2 loss against United in the Community Shield at Wembley on Sunday.
While Mancini may not move for Sneijder, the Italian confirmed he is still keen to sign more players before the transfer window shuts on August 31.
Mancini has already revealed his interest in signing Arsenal midfielder Samir Nasri, while a bid for Inter's Cameroon star striker Samuel Eto'o has also been mooted.
"We need to complete the targets we had at the start of the pre-season. We still have time before the end of the transfer window," he said.
"We need to complete this but I am very positive about my team."
Mancini's plans for the start of the Premier League season -- which kicks off next weekend -- may yet include captain Carlo Tevez after he confirmed the unsettled Argentina forward will report for training on Monday.
Tevez is desperate to leave City after his family returned to Argentina because they were unable to settle in Manchester.
A potential move to Brazilian club Corinthians collapsed last month, while Inter have yet to follow up their reported interest with a firm offer.
For now, Mancini is content to work with Tevez in the hope he can be persuaded to stay and he said; "Carlos will be back on Monday, yes for sure".
Meanwhile, Sir Alex Ferguson took heart from the way United's youthful second half line-up, with an average age of 22, recovered from two goals down in the annual curtain-raiser to the new campaign.
Ferguson sent on youngsters Phil Jones, Tom Cleverley and Jonny Evans at the break and all three gave impressive displays.
But it was Nani's double that finally sunk City and Ferguson believes the Portugal winger will have a major part to play this term even though he left him on the bench for last season's Champions League final.
"Nani had a fantastic season, he was just unfortunate that (Antonio) Valencia came back at a time when we needed a boost and some freshness," Ferguson said.
"Valencia has been terrific but Nani has been great in pre-season and he will start the season. He has always had great potential. Some players take longer than others to mature."
Ferguson also played down fears that new goalkeeper David De Gea may be too inexperienced to play for United after the 20-year-old Spaniard was at fault for City's second goal.
De Gea, signed from Atletico Madrid for ?£18 million, allowed Edin Dzeko's long range effort to beat his late dive, but Ferguson said: "It's difficult to say if he should have saved it.
"It swerved and caught the goalkeeper on the wrong foot. You have to cope with these things. He and the likes of Phil Jones will give us a great future"
Source: AFP
Source: AFP