An independent charity that supports football referees at every stage of the game has accused Cardiff manager Neil Warnock of "desensitising" the abuse and assault of grassroots referees with his repeated criticism of match officials.

Warnock was incensed by several decisions during Cardiff's 2-1 home defeat by Chelsea on Sunday, most notably Blues defender Cesar Azpilicueta's equaliser from an offside position.

Speaking after the match, Warnock said the Premier League was the best in the world but had "probably the worst officials".

The Football Association is understood to be assessing his post-match comments but the 70-year-old will not be punished for his silent protest after the final whistle when he stood in front of referee Craig Pawson and his assistants, glaring at them and shaking his head.

Warnock picked up where he left off on Sunday in a press conference in Cardiff on Tuesday to preview his side's visit to Manchester City.

Once more, he was highly critical of Mike Riley, the head of the Professional Game Match Officials Limited, describing him as "a manufactured referee...almost like a robot" who "knows everything about the rules" but does not understand the game.

"A lot of referees are like Mike Riley and that's why I think we have gone backwards," he said.

The hugely experienced manager also then joked that he had threatened to report his wife Sharon to the FA after she said she would not have stopped him if he had wanted "to thump" Pawson.

"I had to tell her off, I fined her a week's wages because she can't say things like that," he said.

"I told her she's going to have to calm down or I'll report her to the FA. I would imagine she said what 30,000 Cardiff fans would have said. I can't condone that, so that's why I took action against her."

While Warnock was clearly joking, there are some who do not believe quips about hitting match officials are a laughing matter, as reports of abuse and worse are rising in amateur football.

Speaking to Press Association Sport, Ref Support UK chief executive Martin Cassidy said: "We believe Mr Warnock's continued and aggressive criticism of match officials encourages referee abuse at grassroots level and encourages the desensitisation of ref abuse and assaults.

"His actions and comments about 'punching the ref' are of great concern to us and were particularly distasteful, irresponsible and unnecessary, even in jest.

"When Mr Warnock criticises his players for their mistakes as much as he does match officials, then we will give his comments some credence."

The FA and PGMOL have declined to comment on Warnock's most recent outburst and the Referees' Association has not responded to a Press Association Sport request for comment.