Bhutan's Election Commission announced Friday the two top political parties to contest general elections next month, with both the ruling party of the previous government and its former opposition knocked out.

The People's Democratic Party (PDP) -- led by Dasho Tshering Tobgay, prime minister from 2013-2018 -- took 42 percent, the Election Commission said a day after primary polls were held.

The Bhutan Tendrel Party (BTP) came second with 19 percent, eliminating three other parties from the general election on January 9.

Voters travelled from across landlocked Bhutan, which lies squeezed between regional giants India and China and is similar in size to fellow mountain nation Switzerland, to cast their ballots on Thursday.

Bhutanese people voted for the first time in 2008 after political reforms were instituted soon after the start of the reign of the present king. He remains widely popular among the country's nearly 800,000 people.

Former prime minister Lotay Tshering, a physician known for still conducting surgeries on weekends as a "de-stresser" from the pressures of office, stood down last month ahead of elections.

Tshering's party, which had held 30 of the 47 seats in parliament, came in fourth with just 13 percent. The previous opposition was also knocked out.

The Himalayan kingdom is famed for its philosophy of "Gross National Happiness", which sees it benchmark itself on citizen wellbeing instead of economic growth.

Voter turnout on Thursday among the nearly 500,000 registered voters was 63 percent, the commission said.