Indonesia's presidential frontrunner on Monday picked a popular former vice president seen as a formidable political operator as his running mate for elections in July.

Joko Widodo, who won widespread admiration during his time as Jakarta governor due to his common touch, selected Jusuf Kalla, 72, as his vice presidential candidate.

Analysts say picking a veteran politician is a wise move for Widodo, known by his nickname of "Jokowi". Recent polls have shown a Widodo-Kalla ticket would secure a comfortable lead.

While Widodo, 52, has been hailed as a break from previous leaders with deep roots in the autocratic Suharto era, he has never had a role in national politics.

"We are convinced that both of us can bring a movement of change to this country that we love," said Widodo, as he announced Kalla as his running mate in front of a cheering crowd at Jakarta's Gedung Joang museum housing exhibits from the country's independence struggle.

Prabowo Subianto of the Gerindra party, an ex-general accused of human rights abuses during the era of dictator Suharto, is expected to be the only other person who will contest the presidency.

Kalla, a wealthy businessman and chairman of the Indonesian Red Cross, was vice president during current President Susilo Bambang Yudhoyono's first term in office, from 2004 to 2009.

He has argued that he was a key actor behind many of the achievements of that period, from the fight against corruption to a reduction in deadly attacks by Islamist militants.

"Jokowi really needs someone who can help him out, who has experience in governing and the bureaucracy," said Yunarto Wijaya from pollster Charta Politika.

Widodo, from the main opposition Indonesian Democratic Party of Struggle (PDI-P), has long been in the lead in opinion polls before the July 9 presidential election, and surveys show him doing best when Kalla is his running mate.

Widodo has become a political phenomenon since being elected Jakarta governor in 2012. He has temporarily stepped aside from his post as governor to contest the election.

He rose to prominence after serving as mayor of a small town on the main island of Java and has won many admirers with his down-to-earth style.

However Widodo's hopes of an easy ride to the presidency were dealt a blow at legislative elections in April, which set the stage for the presidential polls.

His PDI-P did not do as well as expected, meaning the party has had to form a larger coalition than it might have liked to put Widodo forward for the presidency.