You are not allowed to vote on your family member’s behalf. Voting must be done by the voter in person. Your relative’s name will be removed from the Registers of Electors if he/she fails to vote in the election.  

After the election is over, he/she may apply to restore his/her name to the Registers. He/she will not have to pay a fee if he/she has a valid reason for not having cast their vote on polling day.

Source: ELD

This article is accurate as of Aug 2015.