Tanzania's ruling party on Sunday anointed government minister John Magufuli as its candidate for presidential elections due to be held in October, party officials said.

Magufuli, 55 and currently the east African nation's minister of works, will be widely expected to succeed President Jakaya Kikwete, who will be stepping down after his second and final term.

Presidential, parliamentary and local polls are due to take place on October 25.

The ruling Chama Cha Mapinduzi (CCM) party has been in power since independence in 1964, and currently has two-thirds of seats in parliament.

"This is the man we are sending for the campaign for our party," said parliament speaker and leading CCM member Anne Makinda, after ballots were counted in Tanzania's administrative capital of Dodoma.

The party said Magufuli scored 87 per cent of the votes, beating off Justice Minister Asha-Rose Migiro, a former UN deputy secretary general and ex-foreign minister, and Amina Salum Ali, currently the African Union's ambassador to Washington.

Magufuli had not initially been seen as a frontrunner, but was among three shortlisted from a field of nearly 40 other candidates that included Vice-President Mohamed Bilal, Prime Minister Mizengo Pinda, and former prime ministers Edward Lowassa and Frederick Sumaye.

Tanzania, with over 50 million people, is East Africa's most populous country, with economic growth of more than seven percent, according to the World Bank.

Despite advances, the country "remains very poor by regional and international standards", the World Bank says, with agriculture the key sector, providing a quarter of gross domestic product, and employing three-quarters of the population.

The government has also been criticised for failing to stamp out rampant corruption, and conservationists also say the number of elephants being slaughtered for ivory by poachers is among the highest anywhere on the continent.