The seat of Eden-Monaro is 'marginal'

Prime Minister Scott Morrison has called the federal election for May 18. So, what happens now?

Australians will elect 151 members of parliament (MPs, one from each seat) to the lower house and 33 senators (six per state and two per territory) to the upper house.

Senators have six year terms, so a regular election - such as this one - means only half of the Senate is up for re-election.

A seat that was last won on 60 per cent or more of the two-party-preferred vote is considered "safe" by the Australian Electoral Commission. Between 56 to 60 per cent is "fairly safe" and under 56 per cent is "marginal".

The Yass Valley sits within the electoral division of Eden-Monaro, where the incumbent is Labor member Dr Mike Kelly. Dr Kelly won the electorate by 52.93 per cent in the 2016 election, making the seat marginal.

Eden-Monaro has long been considered a bellwether seat, meaning the result in the electorate is meant to be indicative of the overall result.

There will be an interesting three-cornered battle in Eden-Monaro with Labor, Liberal and The Nationals all contesting the seat. The candidates include Dr Kelly (Labor), Dr Fiona Kotvojs (Liberal) and Sophie Wade (Nationals).

This will be the first time the Nationals have had a federal candidate for Eden-Monaro since the 1990s. Peter Hendy ran for Liberal in 2016 and received 47.07 per cent of votes.

The other candidates that have thrown their hat in the ring so far include Pat McGinlay (Greens), Chandra Singh (United Australia Party), David Sheldon (independent) and Andrew Thaler (independent).

The Greens got 7,177 votes in 2016, while returning candidate Mr Thaler got 981.

These candidates are expected to talk about black spots, roads, aged care, health, education, the drought, employment, small and medium-sized businesses.