Isi Pulu was a founding member of the party that the interim Prime Minister 'Akilisi Pohiva leads.
Mr Pulu, who was first elected in 2002 but missed out in the 2014 election after falling out with Mr Pohiva , said he wants to bring greater accountability to parliament.
He said the democratically-led government had lost its way, leaving people still striving for better living standards.
Despite this, Mr Pulu said he does not harbour any bad feelings over his split with Mr Pohiva, who he believes may be receiving bad advice.