Junta spokesman Idrissa Cherif said 70-year-old Mr Dore had "experience and understanding of Guinean politics". Mr Dore has been a prominent critic of army rule and was hospitalised after a military crackdown on 28 September. The junta seized power in December 2008 but leader Capt Moussa Dadis Camara was shot and seriously hurt last month. Interim leader Gen Sekouba Konate is due to return to Conakry on Tuesday, when he is expected to make a formal announcement of Mr Dore's appointment.
Opposition groups chose Mr Dore as their candidate for prime minister after hours of talks and a vote. The BBC's Conakry correspondent Alhassan Sillah, currently out of the country, says Mr Dore and union leader Hadja Rabiatou Sera Diallo each received 94 votes. But he got the nomination because he has a university degree, our correspondent says. The unions, however, say the vote was not fair. Mr Dore said he would have no problem working with the military, describing Gen Konate as "competent and efficient". "The main thing to do is to make sure that the next election will be fair and credible and to start the restructuring of the armed forces," he told the BBC's Focus on Africa programme. Under the deal, Ms Diallo would become one of two deputy prime ministers. The unions had said the prime minister should not be a politician, as the role should be neutral. But the veteran unionist told the BBC she was now willing to be part of a team and that the future of Guinea was the most important thing
The unions are very powerful in Guinea, having staged several high-profile demonstrations since 2006. They had thrown their support behind Ms Diallo - who our correspondent says is venerated like a god by some unionists.
Mr Cherif told AFP news agency that Mr Dore would steer the transitional government through its "roadmap". He said the administration would consist of 30 members - 10 from the ruling junta, 10 from the opposition, and 10 representatives from the regions.
Following September's crackdown on an anti-junta protest, involving senior politicians such as Mr Dore, several opposition leaders demanded that Capt Camara step down. After reports of a power struggle between his supporters and Gen Konate, Capt Camara agreed last week to take a back seat. In an agreement signed last week, a national election was pencilled in for six months' time. Capt Camara spent weeks being treated in Morocco for a bullet wound after he was shot by an aide on 3 December. Last week he was flown to Burkina Faso, where he is continuing to recover.
A UN report has said Capt Camara should be charged over the September crackdown in which more than 150 opposition protesters are thought to have been killed.
Caspar Leighton BBC News The civilian opposition is clearly not being included in the decision-making process. General Konate is supposedly in charge - but he remains in Burkina Faso allegedly for consultations with Capt Camara, who is weakened after an assassination attempt and has accepted exile. Ordinary Guineans are worried that Capt Camara is still pulling the strings. The agreement reached on Friday was heralded as the breakthrough that could avert disaster in Guinea. But until now it is only an agreement among the military and the civilian opposition has not put its seal on anything.
•From a minority ethnic group in Forestiere region
•Critic of military rule
•Organised 28 September protest, claims he was beaten by soldiers
•Leads the Union for the Progress of Guinea party
•Stood for president against strong-man ruler Lansana Conte in 1993 and 1998
•Has never served in government