"To me fast bowling is so exciting because I haven't even hit my maturity as a fast bowler," he told reporters. "If you ask me if I can go faster, yes, I definitely do think I can go faster."
Lee, 28, who has not played Test cricket for more than a year, told reporters he was frustrated that he had not been selected for the team despite proving his fitness in the one-day arena following ankle surgery.
"It has been very frustrating. It has been close to 15 months since I played a Test match," he said.
"I spent six or seven months getting the ankle right and I come back to a team which is pretty much established and doing well.
Lee, who ranks alongside Pakistan's Shoaib Akhtar as the world's fastest bowler with deliveries around 100 miles an hour (160 kph), said he could bowl faster still.
"I started off bowling in the 140s and two years ago I was bowling in the 150s. The last match I played I bowled 160.8 kph, close to 161.
"The trend is that as I'm getting older I'm getting stronger. I'm still 28, very young, I feel like I'm in the body of a 21-year-old right now because I've had a lot of rest."
