CANBERRA, Oct. 22 (Xinhua) -- Former Australian Prime Minister Malcolm Turnbull has come under fire from the governing Liberal Party for failing to campaign for the party in a key by-election.

The future of the Liberal-National Party Coalition (LNP) government has been cast into doubt after it lost its majority in the House of Representatives in Saturday's by-election in Turnbull's former seat of Wentworth.

Independent Kerryn Phelps claimed victory over Liberal candidate Dave Sharma after a 19-percent vote swing against the government, the largest swing in a by-election since 1992, delivered her a narrow victory.

The by-election was triggered when Turnbull resigned from the parliament after he was deposed as PM by the Liberal Party in August with Scott Morrison installed as leader.

Turnbull did not campaign in Wentworth despite Sharma personally asking the former PM for a public endorsement, instead remaining in the United States on holiday.

Nick Greiner, president of the Liberal Party, accused Turnbull of being "precious," saying that his intervention could have changed the result.

"There are understandable emotions behind him becoming precious, but he could have sent out a tweet that said 'Sharma is the best candidate and you should vote for him'," Greiner said.

Alex Turnbull, Malcolm's son, was vocal on social media campaigning against the LNP in his father's former seat, citing the LNP's inaction on climate policy as a key reason to vote for Phelps.

Morrison refused to buy in to the idea that an endorsement from Turnbull could have saved his majority, saying that was for "others to judge."

However, Sharma said public support from Turnbull would have been "helpful."

"I was in touch with him regularly through the campaign and, look whatever he was willing to provide was helpful," he told Sky News Australia.

"Whatever more he would have been willing to provide would have been even more helpful, no doubt."