The Samoan lobby group, People Against Switching Sides, says it is disappointed to have lost its campaign to keep driving on the right side of the road.
Parliament passed a bill to formalise the planned switch to drive on the left.
The change was voted through despite thousands of people taking to the street to oppose the government plan.
A spokesperson for the group, Georgina Newton, says they were shocked during the reading and passing of the Bill about the way members of the ruling HRPP voted.
"I guess in some ways it was fait accompli from the very beginning, when you look at the outcome of the vote, but a lot's been said since you know that those people were voted in and watch out for the next election don't expect to get voted back in."
However, Ms Newton says the general election is not until 2011 and the issue may be forgotten.