The 15 August challenge comes from the nine Noble MPs in the 26 seat parliament, citing a series of policy mistakes that have taken place recently.
Noble MP Lord Vaea told Radio Australia several independents will support the vote, and he is even expecting some defections from the government.
“We believe that over the last 18 months the government has not performed as we anticipated. The way the PM has been performing we feel he hasn't come up to the standard expected of him.