With the opening of polls in Egypt's first post-Mubarak presidential election, five frontrunners have a reasonable chance of making it to the runoff round of voting on June 16 and 17.

According to most opinion polls, the favourites are Amr Moussa, Abdel-Moneim Abul-Fotouh, Mohamed Morsi, Ahmed Shafiq and Hamdeen Sabbahi.

Campaigners for all five presidential hopefuls have said their respective candidates would make it to the runoff. Informed sources, however, say the runoff is likely to feature two out of three frontrunners, namely, Morsi, Moussa or Shafiq.

"Most probably, it will be Morsi and Moussa [in the runoff round], but those who underestimate Shafiq – and the volume and nature of support he is getting – could be in for a big surprise," said one official.

Recent reports, the same official said, put the Brotherhood's Morsi at the head of the race.

"He's been gaining faster than has been indicated in opinion polls," he said. "He's getting support from beyond the Brotherhood's traditional support base; from those who have benefited from the group's charitable activities, Salafists, and conservative voters, who may have earlier been inclined to support Abul-Fotouh."

Morsi will win the first round with close to 30 per cent of votes cast, the official predicted, while Moussa will probably come in second with around 25 per cent of the vote.

Moussa was expected to finish first overall, before the Shafiq campaign began eating into his vote. A good chunk of Shafiq's support comes from Coptic Christians, and, according to sources at the Coptic Cathedral in Abbasiya, calls have recently gone out to support Shafiq, not Moussa.

"Moussa was a favourite until fairly recently when the leadership of the church – which is currently divided because the acting pope is staying out of politics – was convinced that, unlike Moussa, Shafiq would launch a head-on confrontation with the Islamist trend to curtail its mushrooming powers," said one church source.

According to the same source, portraying Moussa as a politician willing to make deals with the Islamists – and portraying Shafiq as a strongman who can "curtail the Islamists" – has been successful, "despite attempts by some key Coptic figures to argue that what the Copts need is a president who will take their side firmly but talk to other leading political forces," the source added.

Moussa's chances have also been harmed by the "hard work of key businessmen who support Shafiq," who have been giving him "generous financial support and ordering employees to vote for him in return for financial incentives."

Descriptions of Moussa as a "remnant of the former regime" has also cut into his otherwise large share of votes, say sources.

Shafiq could beat Moussa to the runoff if his campaign manages to persuade un-politicised voters that, without a firm man at the top, domestic security will not be restored and Egypt's economy would continue to suffer.

There are reportedly elements within the security establishment very sympathetic to Shafiq, who have been working to promote him in a number of ways, including, according to one source, issuing identity cards to large numbers of people to expand his voter base.

Abul-Fotouh, meanwhile, who has risen in popularity in recent months, appears to have faced a recent decline in support, according to the same well-informed sources. "This is largely due to the Muslim Brotherhood," said an official source.

According to this source and others, the Muslim Brotherhood, which expelled Abul-Fotouh last year over his unilateral decision to contest the presidency, has launched an aggressive campaign against the moderate Islamist candidate.

"They're going to the villages and telling the locals that Abul-Fotouh has abandoned the cause of Islam; that he has liberal women and Copts working on his campaign. And this, of course, has worked against him," said one independent source.

Meanwhile, according to official and independent sources, the Brotherhood has gone so far as to direct financial assistance into the campaigns of some other candidates unlikely to make it to the runoff vote.

Abul-Fotouh's supporters, however, argue that their candidate still has a chance. They say that his impact has already been felt, while the recent decline in support is not dramatic enough to rule him out of the runoff vote.

In some assessments, there could be a runoff between Abul-Fotouh on the one hand and Morsi or Moussa on the other, in which case, the former could win.

However, in the assessment of well-informed sources, a runoff between two Islamist candidates is highly unlikely. At the end of the day, official sources say, Abul-Fotouh remains an Islamist – moderate or not.

In fact, these sources suggest that the Brotherhood's anti-Abul-Fotouh campaign could see Sabbahi come in at fourth place and Abul-Fotouh come in at fifth when official results are announced on Sunday.