There are now to be a series of by-elections for which dates are yet to be set.
Loau's opponent, FAST candidate Papalii Tavita Moala, had filed a petition alleging treating and bribery by Loau during the campaign.
After two weeks deliberation the court decision was delivered on Tuesday and the petition dismissed, as the allegations had not been proved "beyond reasonable doubt".
A counter petition by Loau also failed to prove allegations of treating and bribery against Papalii.
The court dismissed the matter and declared Loau had retained his seat.
The former Manu Samoa rugby hardman is now in his third term as a parliamentarian for Sagaga 1.
Samoa police chief to retire
Samoa's Police Commissioner Fuiavaili'ili Egon Keil is to leave his job in the second week of January 2022.
Media in Samoa reported Fuiavaili'ili said he would not re-apply when his contract term ends at the beginning of next year.
Fuiavaili'ili said it was time to let others take over and lead the force.
He has been the country's top cop for six years, but has been criticised by the new FAST Government and recently returned from medical treatment in New Zealand.
Last week, FAST legal adviser Taulapapa Brenda Heather-Latu said Fuiavaili'ili was a good friend of the former leader of Samoa, Tuila'epa Sa'ilele Malielegaoi, and labelled him as only a "desk sergeant" when he was in the Los Angeles Police.
New police minister Faualo Harry Schuster said on Tuesday the normal procedure for these contracted positions was that the jobs were advertised after each term and the incumbent was free to reapply for the job if they wanted.
Faualo said he had spoken to Fuiavaili'ili and had urged him to reconsider his position.