Turkey's largest group of opposition leaders is seeking to iron out differences and nominate a presidential candidate for the upcoming May elections, Bloomberg reported.

According to polls, less than half of the country's voters are expected to vote for the AKP and Erdogan's nationalist ally, but those opposed to the status quo are split largely between a bloc of six opposition parties and the pro-Kurdish party. Bridging the gaps will be key to an effective challenge, sources said, and the bloc will meet on Thursday to coordinate strategy.

Erdogan's opponents are seeking to stop what they see as a slide toward authoritarian one-man rule. The president has turned a once ceremonial office into a nexus of executive power, but the worst cost-of-living crisis in two decades is dominating the run-up to the election. This has disproportionately hit the poor, usually Erdogan's staunchest supporters.

The president has indicated that he will postpone the election by more than one month, to May 14, which will reinforce the need for opponents to agree on a unified strategy and name a presidential candidate.

The opposition may be more united than in any election in the past 20 years, but its failure to nominate a presidential candidate against Erdogan seems to be playing against it, giving the impression of indecision and weakness, said Tim Ashe, an emerging markets strategist at BlueBay Asset Management. A lot can still depend on the opposition and their ability to convince voters that they are a credible force and can potentially be trusted, he said.

While the opposition bloc has promised to run the country by consensus if it wins the election, Erdogan has dismissed the idea as a return to political and economic instability. Instead, the president is campaigning for the need for continuity in turbulent times.

Opposition leaders have generally agreed on power-sharing and will discuss the nomination of a presidential candidate in early February, sources familiar with the matter said. Kemal Kılıcdaroglu, leader of the alliance's largest party, has nominated himself. Another strategy could be to field multiple candidates to increase Erdogan's chances of losing his majority, triggering a second round that could be easier to win, they added.

A major pro-Kurdish party that is not part of the opposition alliance decided to field its candidate in the first round and could be a deciding factor in the second round two weeks later.

Sources said the opposition alliance has reached a tentative agreement to share the president's duties if he wins. According to them, some party leaders could be deputy presidents and others could be members of the presidential advisory council.  Each party could get at least one cabinet post, and the remaining ministerial seats would be distributed according to their share of the national vote.

Meanwhile, the alliance is working to secure parliamentary representation for the four smaller partners, they say. If successful, the opposition could potentially deprive the AKP and its nationalist ally the HDP of a parliamentary majority.