CANBERRA, Oct. 24 (Xinhua) -- Australian Prime Minister Scott Morrison has come under fire from his own party for planning to send his predecessor to an environmental conference in Indonesia.

Morrison has announced that Malcolm Turnbull, who was deposed as the prime minister in August with Morrison chosen as his successor, will attend the Our Ocean Legacy conference in Bali as Australia's representative.

Barnaby Joyce, who served as the deputy prime minister under Turnbull, said the decision did not "stack up" and Turnbull had destroyed his legacy as the prime minister.

Members of the governing Liberal-National Party coalition (LNP) have expressed anger with Turnbull after he refused to campaign on behalf of the government in his former seat of Wentworth in the by-election triggered by his resignation, which was won by independent Kerryn Phelps.

"He didn't help, basically didn't even send through so much as a text supporting (Liberal candidate) Dave Sharma and, you know, it cost us the majority in parliament. Here's a serious question to be asked, are you going to reward him with a position in ... Bali?" Joyce said on Macquarie Media radio on Wednesday.

"I think he's just angry, angry about ... losing his job. One can only presume he's sort of sulking, but it's something you've sort of got to get over with."

Morrison has defended the decision, saying that Turnbull going on behalf of Australia was in the national interest.

"Former prime ministers continue to have a role to play, I think they should be treated with respect, I think they should be offered the honour to them for the service they provided to their country and they can continue to serve," he told reporters.

"I think sometimes we have got to get above the ruck of personality politics and actually just focus on what the national interest is."