Dyer played for NSW and Australian Under 19 sides, and for NSW colts. He became New South Wales' preferred back up keeper for Steve Rixon when Rixon was injured or was busy on international duty. Notably, Dyer played several games in 1984-85 when NSW won the Sheffield Shield.

When Rixon signed to tour in South Africa, Dyer became New South Wales' first choice wicketkeeper. He was a crucial part of the side which won the Shield again in 1985-86.

1986 Tour of India

Australia's wicketkeeper over the 1985-86 summer was Wayne Phillips, but his form dropped away and Tim Zoehrer was appointed in his place. Dyer was unofficially announced next in line when selected as a reserve keeper on the 1986 tour to India.

Dyer performed strongly in tour games but Zoehrer was first choice keeper for the three test matches.

He played in some one day games, making his ODI debut in the third game. In the fourth ODI he came to the wicket when Australia was 6-136 and he and Steve Waugh put on a 102 run stand off 76 balls. He played in the 5th and 6th ODI.

Dyer also scored a century against Delhi in a tour game.

1986-87 Test debut

Dyer made his test debut during the third test of the 1986-87 Ashes when Zoehrer was injured. Dyer broke his nose during the game but kept playing. He was not required to bat in the game, which was a run-heavy draw.

Zoehrer's aggressive on field behaviour over the summer was causing media controversy and Dyer was increasingly spoken of as a more viable option.^[19] After the 1987 tour to Sharjah, Zoehrer was omitted from the squad to tour India for the World Cup; he was replaced by Dyer.^[20]

1987 World Cup

Dyer was a key part of the Australian team which won the 1987 World Cup.^[21]

Following this triumph, Dyer was appointed captain of NSW for the 1987-88 season.^[22]

1987-88 summer

Dyer began the 1987-88 summer as Australia's first choice keeper as they took on New Zealand. In the first test, Dyer took six catches and scored 8 runs with the bat, as Australia earned a then-rare victory.^[23] In the second test, a draw, Dyer scored 60.^[24]

Catching controversy

In the third test, New Zealand were 1-119 when Dyer claimed a catch off Andrew Jones from the bowling of Craig McDermott. TV replays showed that Dyer had fumbled the ball.^[25] This decision later proved extremely costly for New Zealand because Australia only just narrowly escaped with a draw in the game. (Dyer scored 21 and 4 in the bat.)^[26]

"Dyer has to live with his conscience for the rest of his life — no way can I blame the umpires," said New Zealand's cricket manager.^[27]

Dyer later made a statement saying:

I have not commented earlier because I was in the middle of a Test match and was trying to concentrate on it and also because I, and the Australian team management, felt it would have been inappropriate to comment on umpiring decisions... Given that the ball initially hit my left glove and ended in my right glove, I made a gesture of query to the umpires. However, I honestly believed at the time of the incident, as did my captain and my teammates, that the ball had not touched the ground. One angle of slow motion TV replay apparently indicates that the ball had in fact touched the ground. In the circumstances I can understand Andrew Jones being upset, but I would like Andrew, along with all other interested parties, to know that I acted in good faith.^[28]

Alan Border said, "I had no doubt whatsoever it was taken and I got a shock later when I saw the replays. Greg was v