BRUSSELS, June 11 (Reuters) - European Commission President Ursula von der Leyen appears on course for a second five-year term and Estonia's prime minister and Portugual's former premier are also in line for top jobs, EU diplomats and a senior EU official said on Tuesday.

European Union leaders will gather in Brussels on Monday for a first joint review of the European Parliament election.

They are expected to reach an informal decision on a package of jobs, which also include the chairman of EU leaders' summits and the High Representative for Foreign Affairs, before confirmation at an EU summit on June 28-29, diplomats said.

Von der Leyen's centre-right European People's Party (EPP) remained the biggest group in the election, meaning it will determine who is appointed to the most powerful job in the EU institutions - the head of the executive Commission.

With 13 national leaders belonging to the EPP, Germany set to back von der Leyen and France leaning towards supporting her, she would have the qualified majority she requires - 15 of 27 countries, representing 65% of the EU population.

The other jobs would be given to the Socialist & Democrats, the second largest parliamentary group, and liberal Renew Europe, who are likely to revive their governing alliance.

Former Portuguese prime minister Antonio Costa, is the leading candidate to succeed Charles Michel as European Council President, a role which involves liaising with EU leaders and chairing EU summits.

Portugal's new prime minister Luis Montenegro, leading a rightist coalition, said he would back Costa if he ran and EU diplomats said he also has the backing of German Chancellor Olaf Sholz, a Social Democrat.

INVESTIGATION

Costa stepped down as prime minister last November over an investigation into alleged illegalities in his government's handling of lithium and hydrogen projects, as well as a large-scale data centre. Costa denies wrongdoing.

"Some in the northern countries don't like the fact that Costa is involved in the corruption investigation, but there is really nobody else because the Danish socialists are too anti-immigration," one EU diplomat said.

A liberal would be entitled to the third key post of EU foreign policy chief. Here the leading candidate is Kaja Kallas, Estonia's prime minister, who has taken a hawkish stance towards Russia, with which her country shares a border.

"Kallas will have to convince the southern countries that she will not focus too much on Russia in the job," the EU diplomat said.

The Commission president will also need backing from the new European Parliament, which sits for the first time on July 16.

"I am very optimistic that the president will be voted on already in the July plenary," a senior EU official said, adding this could allow a new Commission to start work in November.

The smooth passage, if confirmed, would be in stark contrast to 2019, when EU leaders wrangled for weeks about the posts.

(Reporting by Philip Blenkinsop, Andrew Gray and Jan Strupczewski Editing by Gareth Jones)