McLaren are in their worst run of form for 18 years and have not won a race since the end of 2012.
"I think Ron's practising to be a motivational speaker, maybe," said Button.
"You know when we're in the position we've been in for 18 months it is not easy. For everyone in the team it is very, very difficult.
"So, no. I think we all need to work harder as a team. We shouldn't be pointing the finger at any individual in the team.
"We've got ourselves into this situation and we have to fight our way out. I don't do things in half measures. I've the experience in Formula One to know you need to give 100 per cent.
"And I always do in the paddock, at the factory, on my phone to the engineers. Everything is 100 per cent."
Dennis had told Sky Sports that Button is "a highly paid Grand Prix driver" and added "Do I want him to try harder? Of course, I do."
-AAP