Fuel prices in Ghana have been by 17%, prompting accusations from the opposition that the ruling party is using its influence to buy votes ahead of an election re-run on 28 December.
The cut was announced on state television late on Thursday. Price adjustments are usually announced by the National Petroleum Authority in the middle of the month.
Inflation in Ghana is currently 17.4%.
The run-off election will be between Nana Akufo-Addo of the governing New Patriotic Party and opposition candidate, John Atta Mills of the National Democratic Congress.
Mr Akufo-Addo received 49.13% of the vote in the first round on Sunday. Mr Mills received 47.92%, according to the latest figures.
The NPP lost control of parliament in Sunday's polls.