Talk in Kabul that presidential vote due in 2014 could be delayed or brought forward by a year, threatening constitutional crisis

Influential Afghans have questioned whether the country's next presidential election can go ahead on schedule in 2014, raising doubts about a vote the west is counting on to lay the foundations of a stable government after foreign combat troops leave.

There has been talk in Kabul of either delaying the vote or bringing it forward by a year, even though both options would strain or break conditions laid out in the constitution.

The independent election commission has said it will not move the date, and no one else has the authority to do so. The last presidential election was delayed for several months in 2009 due to issues with the weather, logistics and security.

The questioning of a schedule fixed by the constitution is a reminder of how vulnerable the framework of Afghanistan's fledgling democracy remains, despite a decade of western military and political support and millions of dollars of aid.

There is growing anxiety among many Afghans about the changes 2014 will bring, even as powerbrokers start manoeuvring to take advantage. The last foreign combat troops are due to return home that year, leaving Afghan police and soldiers to fight the Taliban, and there will be huge pressure for a smooth transition.

But violence is spreading in much of the country. Omar Daudzai, a former presidential chief of staff and one of Hamid Karzai's confidants, said security problems could render a poll impossible unless efforts to bring the Taliban into peace talks bear fruit soon.

"We have no choice but to make progress on the peace effort," said Daudzai, now ambassador to Islamabad and a key player in the Afghan government's efforts to pursue negotiations. "Under the current circumstances, or even under a worse situation if the Taliban's presence becomes more dominant, they will intimidate people from coming out to vote. If a significant proportion of the population can't come out to vote, you can't have an election. No election commission will take the risk."

Daudzai said it was possible some Taliban fighters might participate in the elections as candidates for the presidency or for provincial councils. "If we make progress on the peace front quite a sizeable number of them will stand for election," he said. "If we manage to bring some Taliban leaders into electioneering, that will mean that instead of preventing people to vote they will actually encourage them."

The Taliban often denounce Karzai's government as illegitimate and recently halted preliminary talks with the US government. The outlook for speedy progress on a political process is gloomy.

Some Afghan politicians have proposed bringing the vote forward, arguing that an election in 2014 could bring too much turmoil in an already turbulent year. An earlier date could mean more western security support.

William Patey, the outgoing British ambassador to Kabul, said: "I've heard people talk about that, we wouldn't have any objections to it … all we want is a free and fair election."

He said an election in 2013 was "doable" but had not been formally discussed by western diplomats. "There are perfectly good arguments why 2013 would be a good time … [but] by holding it in 2013 you risk an argument that foreigners brought it forward so they can control it," he said.

It is hard to see what Karzai would gain from cutting short his mandate, when the constitution forbids him from running again. He has repeatedly said he will not seek another term in office, but both Afghan rivals and western diplomats in Kabul are concerned he may use worries about security and stability to extend his rule. According to an influential member of the Kabul establishment, Karzai believes that if elections cannot take place in 2014, "he will hang in there for a couple more years".

A failure to hold elections could create a constitutional crisis and perhaps spur unrest among powerful leaders who for much of the last decade have respected at least the broad outlines of Afghanistan's post-Taliban democracy.

"A new president will allow us to press the reset button, domestically and vis-a-vis the international community," the source said. "Another two years of Karzai could literally drown the country and our international relationships."

Karzai's spokesman said suggestions he wanted to stay in power after 2014 were baseless. "We strongly reject allegations that the president wants to delay the elections. The Afghan government will try its best to make sure the elections happen on time according to the constitution," the spokesman said.

Even if the poll is held on time, the government will struggle with concerns about its legitimacy, after accusations of widespread fraud marred the 2009 presidential poll and the 2010 parliamentary elections.

The election commission is drafting a list of changes to the polling system, including a more transparent arbitration system and improvements to voter registration, which will eventually be presented to parliament as the basis of a new electoral law. There are concerns it is already too late to sort voter lists in time for the presidential election, given the challenges of widespread illiteracy, a huge population without formal identity documents, and worsening security problems.

Abdullah Ahmadzai, the chief electoral officer , said the commission was focused on creating a sustainable solution to the voter registration problems. "Some improvements will be implemented by the 2014 election," he said.

Civil society activists warn that the election commission itself needs reforms to the systems for appointing its members, if the credibility of polls is to improve. Currently Karzai appoints its members directly. Members of parliament are discussing a draft law governing the duties and structure of the commission that would give other groups a say in its makeup.

Jandad Spinghar, executive director of the Free and Fair Election Foundation of Afghanistan, said: "The first stage is independence of the electoral administration. We have plenty of time to amend the electoral law."

The presidential poll is just one part of Afghanistan's election headaches. A system of staggered elections should see the country hold polls for provincial councils in 2013, the presidency in 2014 and parliament in 2015.

In a country where votes are expensive and hugely disruptive, there will be a temptation to defy the constitution and reschedule at least one of those. If the provincial council elections are held on schedule, it could add weight to any attempt to delay the presidential election to 2015 to coincide with the parliamentary vote.