Giannis Antetokounmpo insisted his focus was not on potentially signing a supermax extension with the Milwaukee Bucks.

The two-time reigning NBA MVP has until December 21 to sign a five-year supermax extension with the Bucks in a deal reportedly worth at least $228million.

But, despite the approaching deadline, Antetokounmpo said he was staying focused on his, and his team's, improvement.

"Right now, I'm not focusing on that," he told reporters on Wednesday.

"I know my agent Alex [Saratsis] and [Bucks general manager] Jon Horst and the Bucks ownership are focusing on those discussions.

"I'm just trying to focus on myself, how I can get better, how I can help my team-mates be better, how I can be ready on Saturday to play our first preseason game."

Antetokounmpo looked set to lead the Bucks to a first championship since 1971 last season, but Milwaukee fell to the Miami Heat in the Eastern Conference semi-finals.

The Bucks were the second team ever to have the outright best record in the NBA in two straight seasons and not make it to the Finals in either, along with the Cleveland Cavaliers in 2008-09 and 2009-10.

Antetokounmpo averaged 29.5 points, 13.6 rebounds and 5.6 assists during the regular season, but his free-throw shooting fell away.

He had the third largest season-to-season decline in NBA history among players with at least 600 free-throw attempts in both campaigns, dropping from 72.9 per cent to 63.3.

As the Bucks prepare for another championship tilt, Antetokounmpo was unwilling to put additional pressure on his team.

"I don't believe it's a championship-or-bust situation," he said.

"Obviously, everybody wants to win a championship. I want to win a championship. There's nobody that wants to win a championship more than me – I can guarantee you that.

"But there's steps to that. You've got to keep improving. You've got to keep getting better, and hopefully we can get there this year."

The Bucks begin their NBA campaign against the Boston Celtics on December 23, after three preseason games against the Dallas Mavericks and New Orleans Pelicans.