In the last elections, in 2002, only two parties cleared the 10 per cent hurdle for seats in Turkey's parliament, ensuring an almost two-thirds majority for the AK party.
But this time, the Nationalist Movement party (MHP) and the Republican People's party (CHP) look likely to clear the 10 per cent barrier. If they do, it is expected to cost AK parliamentary seats.
The elections were triggered in part by the AK party's nomination of Abdullah Gul, Turkey's foreign minister, for president.
The nomination of Gul, whose wife covers her head, prompted a reaction from secularists, who held massive rallies in several cities in protest, and the opposition boycotted the presidential vote in parliament.
In response, the government withdrew Gul's candidacy and called the July elections.
Speaking on Saturday in an interview with Barnaby Phillips, Al Jazeera's Turkey correspondent, Gul said that after the elections he would decide whether to again stand for president.
The next government will quickly face new challenges.
It has to tackle rising Kurdish separatist violence in the east and decide whether the army can enter northern Iraq to crush Turkish Kurdish fighters based there - a move that is increasingly worrying the US.
It must also find a compromise candidate for president and speed up EU-inspired reforms or risk an economic backlash.
Analysts say this election is one of the most important in a quarter century because it is key to Turkey's future direction.
Opposition parties say the vote is about defending Turkey's secular system against political Islam, though Erdogan laughs off CHP claims that he wants to turn Turkey, which bridges Europe and the Middle East, into an Iranian-style theocracy.
Some independent, mostly pro-Kurdish candidates are also tipped to win seats in the 550-member parliament.
The AK party's record of economic growth of seven per cent a year on average, falling inflation and record foreign investment has won over many Turks fed up with mismanagement, corruption, fractious coalitions and four military coups in five decades.
The party also secured coveted EU accession talks in 2005 after 40 years of trying.
Erdogan has said he will leave politics if his party fails to win an absolute majority.