Japanese Prime Minister Shinzo Abe swept to a resounding victory in a snap election today, winning a mandate to harden his already hawkish stance on North Korea.

Abe's conservative coalition was on track to win 311 seats in the 465-seat parliament, according to a projection published by private broadcaster TBS, putting him on course to become Japan's longest-serving leader.

Abe was heading for a 'landslide win', the top-selling Yomiuri daily said on its website, as the premier's gamble to hold a snap election appeared to be paying off.

But it was unclear in the immediate aftermath of the vote whether Abe's coalition would retain its two-thirds 'supermajority', requiring 310 seats, as some media had it falling just short.

A 'supermajority' would allow Abe to propose changes to pacifist Japan's United States-imposed constitution that forces it to renounce war and effectively limits its military to a self-defence role.

Abe's Liberal Democratic Party (LDP) benefited from a weak and splintered opposition, with the two main parties facing him created only a matter of weeks ago.  -- Agencies