CANBERRA, July 16 (Xinhua) -- Australian Prime Minister (PM) Malcolm Turnbull has increased his lead as the nation's preferred leader to the widest margin in over two years, according to the latest Newspoll released on Monday.

The poll shows that Turnbull extended his lead over Bill Shorten, leader of the Opposition Australian Labor Party (ALP), at preferred PM to 19 points.

It represents the biggest gap between the two since the lead-up to the 2016 Federal election, in which Turnbull's Liberal National Party (LNP) narrowly held on to power.

According to the poll, 48 percent of Australians believe Turnbull is the better choice as leader compared to 29 percent who chose Shorten.

Despite Turnbull's position as the preferred PM, 51 percent of respondents to the poll picked Shorten's ALP on a two-party-preferred basis, the 36th consecutive loss for Turnbull's LNP.

Ahead of the crucial by-elections both the ALP and LNP lost a single point from their primary votes according to Newspoll, falling to 36 and 38 percent respectively.

The combined primary vote for the conservative LNP and One Nation Party was 45 percent while the progressive ALP and Greens held a narrow lead at 46 percent.