The Italian, who looks increasingly likely to leave at the end of the season or before, described their inability to hold on to victory as 'unacceptable' and questioned their spirit.
Goals by Harry Kane and Ivan Perisic appeared to have sealed a win that would have taken Tottenham into third place but Theo Walcott pulled one back and then Tottenham substitute Pape Sarr gave away a 90th-minute penalty that was converted by James Ward-Prowse in stoppage time.
See all the match details on Flashscore
Tottenham have 49 points from 28 games but Newcastle United, in fifth, have 47 from 26 games.
"For me it was not a penalty. But the worst situation is what was happening on the pitch. What was happening in the last few months. What is happening in my second season" Conte told reporters.
"I think that it's the right moment to speak because I think that after this performance, for me this is unacceptable. We are winning 3-1, in control and concede two goals and Fraser (Forster) made saves. It's better to go into the problem, we are not a team. We are 11 players that go into the pitch.
"I see selfish players, players that don't want to help each other and don't put their heart."
Conte's tactics are regularly questioned by Tottenham fans who appear to have lost patience with his methods.
But Conte turned his ire on the players.
"Before today I try to hide the situation and improve the situation with words," he said. "About tactical and technical, it's one situation, another is the desire, the fire that you need to have in your eyes, your heart.
"You need to have this in every moment. This season compared to last, now we are worse in this aspect. When you are not a team you cannot improve."
Conte's verbal onslaught suggests all is not well in the changing room and sounded like the words of a manager ready to call time on his Tottenham tenure having managed to get them to fourth place last season after replacing Nuno Espirito Santo.
"The club has the responsibility for the transfer market, the coach has the responsibility. But the players, where are the players? I see only 11 players that play for themselves," he said
