Delegates from Afghanistan, Pakistan, China and the United States sat down on Monday for talks to resurrect a stalled Afghan peace process and end nearly 15 years of bloodshed, even as fighting with Taliban insurgents intensifies.

Senior officials from the four countries are meeting in Islamabad to launch what they hope will lead to negotiations involving the Taliban, who are fighting to impose their strict brand of Islamist rule and are not expected at Monday's talks.

The Pakistani prime minister's foreign affairs adviser, Sartaj Aziz, opened the meeting, saying the primary goal should be to convince the Taliban to come to the negotiating table and consider giving up violence.

"It is therefore important that preconditions are not attached to the start of the negotiation process. This we argue will be counterproductive," he said.

"The threat of use of military action against irreconcilables cannot precede the offer of talks to all the groups."

Afghan Deputy Foreign Minister Hekmat Karzai and Pakistani Foreign Secretary Aizaz Chaudhry were joined by representative from the United States and a senior Chinese official.

Renewed peace efforts come amid spiralling violence in Afghanistan, with last year, after the withdrawal of most foreign forces at the end of 2014, one of the bloodiest on record.

In recent months the Taliban have won territory in the southern province of Helmand, briefly captured the northern city of Kunduz and launched a series of suicide bombs in the capital, underlining how hard Afghan government forces are finding it fighting on their own.

Peace efforts last year stalled after the Taliban announced that their founder, Mullah Mohammad Omar, had been dead for two years, throwing the militant group into disarray and factional fighting over a new leader.

The Taliban, who were ousted in 2001, remain split on whether to take part in talks, with some factions opposed to any negotiations but others considering joining talks, senior members of Taliban groups said last week.

Officials are keen to limit expectations of a quick breakthrough.

Afghanistan has said the aim is to work out a road map for peace negotiations and a way of assessing if they remain on track.