Women's representation in parliaments is most likely to increase where there is some sort of system of quotas, an analysis of international elections held last year shows.

However, the US bucked the trend by recording an historic number of women elected without any kind of quotas, the study by the Inter-Parliamentary Union found, a result which was attributed to the large number of women candidates.

Government MPs on Tuesday defended prime minister-elect Tony Abbott's decision to appoint only one woman - Julie Bishop - to his 19-member cabinet.