Australian prime minister Julia Gillard praised Baroness Thatcher for her "strength of conviction".
She said: "Her service as the first female prime minister of the United Kingdom was a history-making achievement.
"Her strength of conviction was recognised by her closest supporters and her strongest opponents.
"I extend my sincere condolences and those of my fellow Australians to her family and friends."
More top news
A man has been rescued by firefighters - after getting his head stuck inside a washing machine.
Late-running passengers who attempt to pass through security with less than 30 minutes before their flight departs will now be stopped.
A Ukrainian pilot who spent two years in prison in Russia has been sworn into national parliament after being released last week.