Sir Alex Ferguson has escaped censure from the Football Association for his confrontation with the referee, Mike Dean, during his Manchester United team's 4-3 home win over Newcastle United on Boxing Day. But Alan Pardew, the Newcastle manager, has suggested that Dean ought to have sent off Ferguson, as he described the pressure that the referee was put under as "tough to take".

On the day that the FA began to consider whether to take further action against Roberto Mancini and Harry Redknapp, the managers of Manchester City and Queens Park Rangers, for their public criticisms of the match officials during the Premier League's Boxing Day programme, Ferguson's behaviour came under scrutiny.

Pardew, who said that he did not speak to Ferguson after the game, took the unusual step for a British manager of being critical of his Manchester United counterpart. To him Ferguson's conduct was worthy of dismissal. "I think Mike Dean might feel slightly disappointed he didn't do something about it," Pardew said. "I think the pressure that was on him was tough for a referee to take. Sometimes when you reflect on a game you think you might have acted differently. You do that as a manager and I think he might have done that as a referee.

"But it's an emotional game and apparently they had a cordial discussion. I've had a few of those myself and sometimes I've ended up in the stands as a result of that cordial discussion."

The United manager was angry after Dean overruled his assistant Jake Collin to allow Newcastle's second goal to stand, after it was ruled out for offside. Newcastle's Papiss Cissé was beyond the final defender when Danny Simpson's drive was turned into his own net by Jonny Evans in the 28th minute. Ferguson approached Dean as he made his way out for the second half before he rounded on Collin and the fourth official, Neil Swarbrick.

Dean made no mention of any extraordinary incident in his match report, which he filed to the FA, and he and his assistants are understood to have regarded the conversations with Ferguson, despite their apparently heated nature, as being rational and reasonable.

The fact that Dean did not banish Ferguson to the stands was an indication that the manager had not used abusive or insulting language towards the officials, or questioned their integrity. There was a difference of opinion about the interpretation of the rules but it did not cross the borders of acceptability. As Dean did not flag up any improper conduct from Ferguson to the FA, it has taken the matter no further.

Pardew was also slightly surprised that Robin van Persie was not charged by the FA, despite appearing to strike the Newcastle captain, Fabricio Coloccini, in the face. "I think there were a lot of things the FA could look at," Pardew said. "But it seems they are looking at none."

The FA is, however, looking into the post-match comments of Mancini and Redknapp. Mancini was furious with Kevin Friend after City's 1-0 defeat at Sunderland, suggesting that "maybe the referee ate too much for Christmas". He felt Friend had missed a foul on Pablo Zabaleta in the build-up to Adam Johnson's decisive goal and he said it was "impossible two men couldn't see it," referring to Friend and his linesman.

Redknapp lost his cool after a pair of decisions went against Rangers in the 2-1 home defeat by West Bromwich Albion; the first, a nudge on his goalkeeper Rob Green that played a part in West Brom's second goal and the second, the non-award of a late penalty when Liam Ridgewell appeared to handle.

"I asked the linesman how he didn't see that penalty – it was the most blatant handball you could wish to see but he said it was murky down there in that corner and he couldn't make it out," Redknapp said. "Maybe he should go to Specsavers. I thought they were both awful decisions. Scandalous decisions."

The FA takes a dim view of managers questioning the capability and integrity of match officials and it is expected to write to both Mancini and Redknapp in order to ask them for explanations. The managers would have three days to respond and the FA could then decide to bring charges of improper conduct, which can carry touchline bans.