Miami Heat star LeBron James has revealed his frustration at having to leave game one of his team's NBA Finals against the San Antonio Spurs because of cramp.

James limped out of the contest with just under four minutes remaining, with a broken air conditioning system at the AT&T Center leading to stifling temperatures which ultimately caused problems for a number of players.

"I'm feeling better than I did when I came off the floor," James told reporters after the contest.

"I was going to try to give it a go, and 'Spo said 'No.' You know, after I came out of the game, they kind of took off. And it was frustrating sitting out and not being able to help the team."

Game two between the sides takes place on Sunday, with the problem at the venue having now been resolved.