Citizens of New Zealand and Germany living in Australia will get to cast their ballots in their country's elections, with both nations heading to the polls this weekend.

New Zealand decided on Saturday whether incumbent Bill English will remain as Prime Minister or if Jacinda Ardern will take the top job after being leader of the Labour Party for a matter of weeks.

Meanwhile, Germans will vote on Sunday to determine whether Chancellor Angela Merkel will receive a fourth term in office.

It's estimated there's more than 31,000 Kiwi citizens in Australia who are eligible to vote, either through a postal vote, online or at designated polling places.

Among them is Ali Bulbul, 22, who moved to Australia in 2013 and said housing affordability has become one of the leading issues in the election.

"It's become one of the biggest issues in New Zealand, and house prices are in the upper echelons, especially in Auckland," he said.

When the election was announced in February, many assumed the result would be a slam-dunk for National Party leader Bill English, who took over from John Key in December.

However, with Jacinda Ardern becoming Leader of the Opposition seven weeks ago, polls have narrowed in the time leading up to election day.

"Jacinda Ardern has captivated the nation and has given Labour a chance," Mr Bulbul said.

Scullin resident Yash Vyas, 22, is also taking part in the election and has already voted online.

He also said housing affordability was a leading issue in the election, although he said elections across the ditch were starting to look more like those in Australia.

"New Zealand is becoming a bit infected with the Australian disease of being obsessed with opinion polls," he said.

"Hardly anyone talked about polls at the last election, and now polls have suddenly become a big deal, and caused the old Labour leader to step aside and have Jacinda Ardern take over."

Despite Germany and New Zealand being thousands of kilometres apart, both nation's elections are remarkably similar, using a mixed-member proportional system.

As well as elect a member for their electorate, voters also get a second vote where they vote for a party directly.

For instance, if a party receives 10 per cent of the vote, they are entitled to 10 per cent of the seats in the parliament.

German citizen and Canberran Ivo Seitenzahl has already voted in his country's election, having sent off his postal vote several weeks ago to ensure it's received on time.

With multiple minor parties contesting the election, including the far-right AfD party which is expected to poll as high as 12 per cent, Mr Seitenzahl said he was looking to the major parties for his vote.

"I'm a believer in established parties, especially with things like Brexit and Donald Trump, and unestablished people getting into power has little appeal to me," he said.

Among the leading issues in the election has been Germany's immigration policies as well as its place in the European Union following Brexit.

"This is the most important election in the EU because Germany is the largest economy," Mr Seitenzahl said.

"The future of the EU is a major issue and it's mostly been related to Brexit."