Former world No.1 Maria Sharapova says smoke was behind the decision to call off her Kooyong Classic match late in the second set when she started to succumb to the tough conditions.

Taking on German Laura Siegemund in the Australian Open warm-up exhibition tournament with heavy smoke blanketing Melbourne, the players and officials decided to stop play at 5-5 in the second set.

World No.72 Siegemund had won the first set 7-6 (7-4).

Sharapova said she felt a cough coming on as the match stretched past two hours with temperatures on court around 40 degrees.

Maria Sharapova struggled with the heavy smoke hanging around the courts at the Kooyong Classic Mike Owen/Getty Images

"I started feeling a cough coming toward the end of the second set but I've been sick for a few weeks so I thought that had something to do with it," Sharapova told SBS after the match.

"But then I heard Laura speak to the umpire and she said she was struggling with it as well.

"We were out there for over two hours so from a health stand point it's the right call from officials."

On the back of a tough run with injuries, Sharapova's ranking has slipped to world 145.

She won the Australian Open in 2008 and has reached the final a further three times.

Despite the decision, Bulgarian Grigor Dimitrov and Croatian Borna Coric still took to the Kooyong court for the second scheduled match.