Here's the deal. You get two votes because New Zealand voters chose a new voting system called Mixed Member Proportional representation (MMP) in a referendum in 1993. It was used for the first time at the 1996 election. Germany has used the MMP voting system since 1949.

The old system was called First Past the Post (FPP). Under FPP, you had one vote for your electorate and the candidate who won the most votes became your MP. Usually one party won more than half of all the electorates and became the government, even if it didn't get more than half of all the votes. MMP makes it difficult for a party to win a majority of parliamentary seats and govern by itself.

When you vote in a general election now, you get two votes, both of which are on a single ballot paper.

Your Party Vote is a nationwide vote for the political party you most want to be in Parliament.

Each party's share of all the Party Votes decides its overall share of all the 120 seats in Parliament. It means that if a party wins 10% of the Party Votes, it gets around 10% of the seats in Parliament - that's 12 seats.

Your Electorate Vote is for the person you want to be the MP for your local area - the local electorate. The person who gets the most Electorate Votes in each electorate is elected MP for that seat.

Each electorate has roughly the same total population, including Maori electorates. As a starting point, the South Island has 16 general electorates guaranteed. For the 2002 and 2005 elections, the number of electorate seats for the entire country increased from 67 to 69. There are 7 Maori electorates based on the proportion of Maori electors who wanted to be put in Maori electorates rather than general electorates. The number of party list seats is 51, so we have 120 MPs.

So how do we work out who becomes an MP?

The person who wins the most Electorate Votes in each electorate becomes its electorate MP.

We work out which parties have qualified for a share of all the seats in Parliament. To qualify a party has to win at least 5% of all the Party Votes or have won at least one seat for an electorate MP.

Once we know which parties have qualified, all the Party Votes cast for each of these parties are used to work out the total number of seats the party should get - if it's 20% they should get about 24 seats. Then we look at how many electorate MPs each party has won - if they won 20% electorates and 20% of the Party Vote, they get 4 list MPs. This way the party has its correct proportion of the total number of seats in Parliament.  The actual calculations are done using a special formula.

The list seats are filled by people off each party's list. Those at the top of the list have a better chance of becoming an MP. Each party decides the order of the candidates on its list before the general election.

All lists are sent to each elector before election day. If a list candidate wins an electorate seat, their name comes off the list and everyone below them moves up one place.