Harris, 83, was already facing 13 child sex offences, dating back to the 1980s, as part of an investigation that has led to the arrest of more than a dozen celebrities.
Prosecutors said the new counts relate to alleged offences against three females, one aged seven or eight in 1968 or 1969, one aged 14 in 1975 and one aged 19 in 1984.
The Crown Prosecution Service said the alleged offences related to one existing complainant and two new complainants. Harris had already appeared in court to face nine counts of indecent assault related to two girls aged under 16 in the 1980s and four counts of making indecent images of a child last year.
Harris, who have lived in Britain for over 50 years, is due to appear in court in London to enter a plea on Jan. 14 and a trial date is set for April 30.
His lawyer was not immediately available for comment following news of the new charges but has indicated that he intends to plead not guilty to all charges.
Harris was arrested in March by British police investigating allegations of child sexual abuse as part of an investigation triggered by revelations that the late BBC TV host Jimmy Savile was a prolific child sex abuser.
Harris has been a family favourite in Australia and Britain for more than 50 years, hosting TV shows and producing chart hits including "Two Little Boys" and "Tie Me Kangaroo Down, Sport" while playing the didgeridoo and his own invention, the wobble board.
The child abuse investigation, called Operation Yewtree, was set up after it emerged following Savile's death in 2011 that the TV star of the 1970s and 1980s committed sex crimes on an unprecedented scale over six decades.
The operation developed three strands: one looking at Savile, a second at allegations against "Savile and others", and a third on complaints arising against people unconnected to Savile. Harris fell into the third category.