Costa is currently refusing to return to Chelsea after being informed at the end of last season that he was not in the plans of Conte entering the 2017-18 campaign.
Costa recently gave an explosive interview to the Daily Mail where he confirmed that he would not be returning to Chelsea, but Conte has laughed off the striker's outburst.
"It is great. I can tell you that everyone who works in Chelsea knows very well what happened with him last season. It's funny, this interview. I'm not interested to continue this issue. He is the past," Conte told reporters.
Costa scored 20 times in Chelsea's 2016-17 Premier League title-winning campaign, but the 28-year-old is said to have had a strained relationship with head coach Conte in the second half of the season.
Chelsea will travel to Tottenham Hotspur on Sunday afternoon looking to bounce back from a 3-2 defeat to Burnley on the opening weekend of the new Premier League campaign.