Wide support ... Jakarta governor and presidential candidate from the Indonesian Democratic Party-Struggle (PDI-P) party Joko Widodo and his wife Iriana.

Wide support ... Jakarta governor and presidential candidate from the Indonesian Democratic Party-Struggle (PDI-P) party Joko Widodo and his wife Iriana. Photo: Reuters

Indonesia's oldest political enemies are edging towards joining forces to propel popular Jakarta governor Joko Widodo to the presidency.

Golkar, the party of strongman Suharto is talking with the party which grew out of the Suharto-era opposition, the Indonesian Democratic Party of Struggle (PDI-P), with a view to supporting Mr Joko as president and his agenda in parliament.

Though nothing is yet signed, the candidates for the two parties, Mr Joko (known as Jokowi) for PDI-P and businessman Aburizal Bakrie for Golkar, appeared together late on Tuesday at a traditional market in Jakarta to announce their "cooperation".

"This a further step towards forming a coalition. If we think we match, I'll talk to PDI-P chairwoman Megawati [Sukarnoputri] and Jokowi," Mr Bakrie said.

Mr Joko said the two nationalist, secularist parties had much in common, but added a strong rider to maintain his image as a cleanskin in a country rank with money politics and dealmaking.

"We want to keep the cooperation pure, so we won't talk about [giving out posts such as] vice president or ministers," he said.

Mr Joko has not announced a running mate despite fevered speculation leading up to the nomination deadline next Monday.

A coalition would align the two parties which won most votes in the parliamentary election, and form the backbone of a potential majority in the lower house, or DPR.

If it comes to be, particularly on Mr Joko's terms, the coalition would signal that Golkar has given up entirely on getting the desperately unpopular Mr Bakrie elected as president against Mr Joko.

It would also be another sign that Golkar is the ultimate pragmatist that will do almost anything to stay on the government benches.

The announcement made it clear that Golkar's earlier coalition talks with Mr Joko's presidential rival, former general Prabowo Subianto, have come to nothing.

The potential deal is extraordinary even in Indonesia's byzantine political scene.

Golkar was formed under Suharto's New Order in 1971 to contest sham elections that gave a patina of electoral legitimacy to his rule. Real opposition was eliminated and Suharto's party won crushing parliamentary majorities at each of the six elections it contested.

PDI-P grew out of the tame, state-sanctioned opposition, the Indonesian Democratic Party, or PDI, which was so dysfunctional that in 1977 Suharto was forced to appoint his Home Affairs minister to run its party congresses.

The party was reinvigorated and added the word "Struggle" to its name in 1998 under the leadership of Megawati Sukarnoputri, the daughter of Indonesia's first president, Sukarno. Stronger opposition was part of the impetus for the collapse of the New Order regime in 1998 and Megawati led her party to near victory in the post New Order election in 1999.

Golkar's deputy secretary general, Tantowi Yahya, said if a deal was signed it would be the first time in government that the two parties had formed a coalition.

Mr Joko, universally known as Jokowi, is the runaway favourite to win the election. But, like his opponent, Prabowo, he is busy talking to the other parties in Indonesia's 10-party parliament to try to form a workable majority for the five-year term that starts in October.