Leaders arrive for debate

Prime Minister Malcolm Turnbull and opposition Leader Bill Shorten have both arrived at a western Sydney RSL club to face off in the first debate of the election campaign.

The pair will field questions from undecided voters at a "people's forum" in the marginal seat of Macquarie held by Liberal MP Louise Markus.

Protesters have gathered outside the Windsor RSL club rallying against the proposed second Sydney airport and supporting climate change action and Gonski school funding.

Mr Turnbull won the coin toss and will deliver his opening address first.

The debate kicks off from 7pm (AEST).