SYDNEY (Reuters) - Australia’s new prime minister extended his party’s nascent recovery, one widely watched opinion poll showed on Monday, six days before a crucial by-election, but the main Labor opposition still holds a landslide-sized lead before elections due by May.

FILE PHOTO - Australian Prime Minister Scott Morrison speaks during a news conference at Parliament House in Canberra, Australia, September 19, 2018. AAP/Lukas Coch/via REUTERS

The Newspoll, published in The Australian newspaper, showed the ruling Liberal-National coalition trailing Labor 47 percent to 53 percent on a two-party preferred basis, under which votes for minor parties are redistributed according to Australia’s preferential voting system.

The gap between the two main parties, twice as wide a month ago, tightened by two points since the previous poll.

However, another poll in The Sydney Morning Herald showed the gap between the government and Labor widening significantly. The Herald’s Fairfax-Ipsos poll, based on a smaller sample than the Newspoll, showed Labor leading 55-45, an increase of four points since September.

Both polls suggest a resounding defeat for the government at a general election, which must be held by May.

Nevertheless, Prime Minister Scott Morrison did perform better with voters than Malcolm Turnbull, the man he replaced in a party-room coup in August, on a range of Newspoll personal measures including “capable of handling the economy”.

Morrison is also seen as more capable of delivering tax cuts, a key policy battleground where he burnished his credentials last week with a promise to reduce taxes on small businesses.

“He’s doing better than Turnbull. That’s not what you would have expected three months ago,” said Haydon Manning, a political science professor at Flinders University in South Australia state.

“He seems to have a way with words, or more in common with the average Australian, especially where it counts in the marginal, outer-urban electorates,” he said.

However, Morrison faces a by-election on Saturday in Turnbull’s harbourside Sydney seat, where voter anger over the revolving door of political leaders has made a once-safe Liberal district a close contest.

The stakes are even higher because the center-right coalition clings to power by a one-seat margin in parliament, which means a loss at the by-election would force Morrison to strike an agreement with independent lawmakers to continue in minority government.

By-elections typically produce strong swings against sitting governments, with the affluent seat of Wentworth seen as particularly vulnerable because of Turnbull’s personal popularity.

The strongest challenger in the seat, polls suggest, is popular independent Kerryn Phelps, who has promised to allow Morrison to continue in minority government.