He gained the support of three other MPs, including Glenda Jackson.
On 9 February it was announced the referendum proposal had only gathered the support of 4 out of 100 MPs.
In the 2002 general election, Sopoanga had obtained the support of just 8 MPs (himself included) out of 15.
The four parties need to elect a new president which will be impossible without having the support of at least 8 Communist MPs.
He was sworn in as Prime Minister with the support of just 64 MPs.
This gained the support of 38 other MPs from all major parties.
The campaign have the support of 87 MPs to date who have all signed the Pledge.
In order to be nominated, they must have the support of 30 MPs or 30,000 voters.
Candidates need the support of 12.5% of the parliamentary Labour party, or 33 MPs.
His rival Nick Clegg announced the support of 33 MPs.