KABUL (AFP) - Afghan President Ashraf Ghani marked his first 100 days in power on Tuesday, still struggling to form a government as a new political stalemate threatens to fuel the Taleban insurgency.

The deadlock over senior cabinet positions has underlined the challenges of running a "unity government", which was formed after an election mired by fraud and disputed results.

Mr Ghani was eventually inaugurated on September 29 after agreeing to a power-sharing deal with his poll rival Abdullah Abdullah, who was appointed "chief executive" - a new role similar to prime minister.

The deal was seen as saving Afghanistan from the risk of imminent civil war, but it was soon bogged down in disagreements over which side's loyalists would take key roles such as interior and defence minister.

Mr Ghani has repeatedly missed his own deadlines on forming the government and asked Afghans to show patience.

The political vacuum comes at a sensitive time as Taleban insurgents push to exploit the end of Nato's combat mission on December 31 after 13 years of fighting.

About 17,000 foreign troops will remain in Afghanistan this year, focusing on training the Afghan security forces and conducting a limited counter-terrorism mission.

Essential aid money from donor nations could also be held up if no government is formed.

"The delay has emboldened the enemy to step up attacks, and undermined the legitimacy of the unity government because security has deteriorated and the economy is down," political analyst Mia Gul Waseeq told AFP.

"The international community wants an accountable and corruption-free cabinet."

Mr Ghani hit the ground running when he signed a long-delayed security deal in his first full day in office.

The pact allowed US-led troops to stay in Afghanistan beyond 2014 - a step seen as crucial to beating back the Taleban, but which had been rejected by Mr Ghani's predecessor Hamid Karzai.

Mr Ghani has worked to improve badly-frayed ties with Washington, Afghanistan's biggest donor, and also with Pakistan, which has an influential role as insurgents seek safe havens on both sides of the border.

A web project called Sad Roz ("100 days") said out of 110 verified government promises, 83 were unstarted, 23 in progress and four achieved.

The achieved goals were the post-2014 security deal, an access to information law, abolishing one bureaucratic department and lifting a travel ban on a New York Times reporter.

Mr Ghani has also re-opened investigations into the collapse of Kabul Bank - the single biggest corruption scandal since 2001.

"There is no news from the national unity government, and the Afghan people are fed up with it," said Hamdard Ghafoorey, a civil society activist in Kabul.

Allocating ministries is particularly difficult due to Afghanistan's ethnic divisions.

Mr Ghani, an ex-World Bank economist, is largely backed by Pashtun tribes of the south and east, while Abdullah, a former anti-Taleban resistance fighter, draws his support from Tajiks and other northern groups.

"My understanding is that the supporters of both teams have made a lot of demands from both leaders," Ahmad Khan, a key supporter of Abdullah, told Tolo TV news.

"Our predictions about the cabinet being appointed did not come true. Now it depends on the two leaders (coming to a deal)."