Former prime minister Bob Hawke, 88, was admitted to the Royal North Shore Hospital on Monday evening.
Mr Hawke's condition was unknown but a Labor representative said he was admitted for tests after experiencing some "minor wobbles", according to reports.
"Hawkie is fine and anxious to get home and back to his cigar and crosswords", a source close to the family said.
Mr Hawke's wife Blanche d'Alpuget told The Daily Telegraph her husband was "OK".
The hospital would not make any comment on Mr Hawke.
"I can confirm on background that Bob is fine," a Labor spokesman said in a statement.
"(He's) Just in hospital for some minor tests, nothing serious."
The former ALP leader served as Australia's 23rd prime minister from 1983-1991 and led Labor to four consecutive election victories.
Mr Hawke's place in the Labor pantheon was formally acknowledged in 2009 when he became only the third person to be awarded national life membership of the party.
Last Tuesday, Mr Hawke flew to Perth to watch Kim Beazley, former leader of the national Labor party, sworn in as Governor of Western Australia.
