The Hollywood Reporter were among the first to release the footage, which shows how air pilot Hal Jordan, played in the film by Ryan Reynolds, becomes Earth's protector against the alien Parallax.
Despite the film's producers warning that the special effects displayed in the clip are not entirely finished, the expanded trailer provides the first significant look at the Green Lantern's home planet Oa.
Geoffrey Rush also features in the footage as the voice of Jordan's guide Tomar-Re, following confirmation of his involvement with Green Lantern earlier this week.
Earlier today, Reynolds confirmed that he would be interested in starring in potential Green Lantern sequels if the first film proves to be a success.
Green Lantern is due for release in UK and US cinemas on June 17.
Watch the WonderCon footage of Green Lantern below: