The Magpies legend, who has three games remaining of his initial eight-match stint at the helm to save the club from relegation, has imposed a new code of conduct since taking charge at St James' Park.
Troubled midfielder Joey Barton has been suspended by the club until further notice after his red card in the defeat against Liverpool which was followed by reports of a dressing room bust-up with Shearer.
And the Toon manager insists his players must be 100 per cent professional as they look to overcome the three-point gap to safety, starting with Monday night's vital Tyne-Tees derby against fellow strugglers Middlesbrough.
There have been widespread reports that the former England skipper is ready to extend his stay in the North East even if Newcastle are relegated, and his demands for team discipline hint that he could already be making longer-term plans.
StandardsShearer said: "I'm not interested in what's gone on in the past. I was aware of things, of discipline, or lack of it, and people have said I've come in and tried to instil discipline and rule with iron rod. But that's not the case.
"There was a fine system in place. I've increased that. Make your own mind up why. I'm just asking players to be on time for work and I don't think that's too much of a problem, particularly when it's 10 o'clock in the morning.
"I'm not asking anyone to do anything ridiculous. I'm just asking for common sense, to be in on time for training to adhere to the standards that Bobby Robson or Kenny Dalglish asked of me.
"We're a professional football club, you have to be professional and that's all I'm asking. It's important for players to come in and feel relaxed to enjoy training and have a smile on their face but it's also very important to be disciplined and professional in what we do. After all, it's a professional sport and we're all getting very well paid for it.
"Every successful club has a discipline side and a code of conduct and this one's no different. There are more important issues but if you take care of the little things then the big things might take care of themselves and things might start to happen results-wise because of it."