JAKARTA • Candidates vying to be the next governor of Jakarta pulled out their parties' big guns at the weekend, as the campaign enters its final stretch.

Former presidents Megawati Sukarnoputri and Susilo Bambang Yudhoyono as well as 2014 presidential candidate Prabowo Subianto were all out to rally support for their picks to lead the capital.

With just days before the official cooling-off period kicks in at midnight on Saturday, and voters set to cast their ballots next Wednesday, the race remains tight, although recent snap polls seem to favour the incumbent Basuki Tjahaja Purnama.

Mr Basuki, who is better known as Ahok, and his running mate Djarot Saiful Hidayat, were early favourites, until the former was accused by Muslim hardliners of insulting Islam and later indicted for blasphemy last December.

The pair backed by Ms Megawati's Indonesian Democratic Party - Struggle (PDI-P) has since had to contend with rivals, who unlike Ahok - a Chinese and a Christian - are Muslims.

The results of snap polls over the last few months saw Ahok's lead in the popular vote exchanged between the Gerindra Party pair of former education minister Anies Baswedan and businessman Sandiaga Uno, as well as former army major Agus Harimurti Yudhoyono and veteran bureaucrat Sylviana Murni from the Democratic Party.

The Democrats and Gerindra are led by Dr Yudhoyono and Mr Prabowo respectively.

The most recent polling, released by Charta Politika - a leading political think-tank in Jakarta - last week, however, shows Ahok-Djarot (36.8 per cent) taking over the lead from Agus-Sylviana (25.9), who also lost ground to Anies-Sandiaga (27).

A few other polls in recent weeks have also indicated similar trends.

The electability of Mr Agus fell after the recent debates organised by the Jakarta General Elections Commission, said observers.

But with none of the candidates securing more than 50 per cent of support thus far, Charta Politika executive director Yunarto Wijaya expects the race to go into a second round of voting.

This is where the pair with the lowest votes in the Feb 15 polls will drop out, leaving the remaining two to face off for the post in another round of voting.

Professor Ikrar Nusa Bhakti, a veteran political observer from the Indonesian Institute of Sciences, however, points to the "undecideds" as the real game-changers.

"The portion of undecided voters is 12 per cent and they could decide who the winner is," he added.

A neutral lawmaker, who spoke to The Straits Times on condition of anonymity, agrees, adding that "round two is where Ahok and Djarot will need to fight hard to garner the split or undecided voters".

Francis Chan