Theresa May will host Nato's general secretary in Downing Street amid speculation the UK could be asked to send more troops to Afghanistan.
Jens Stoltenberg will meet the Prime Minister in Number 10 for talks ahead of a summit meeting of Nato leaders in Brussels on May 25.
Leaders of Nato countries been told to think about their military levels in Afghanistan as the US looks to increase its presence by sending at least 3,000 extra troops.
The US has written to Nato countries about the 13,000-strong presence in Afghanistan and "future contributions" will be considered at the Brussels meeting, a Nato official said.
Around 500 British troops are already in Afghanistan in training and mentoring roles as the local security forces continue to battle the Taliban.
The issue risks becoming caught up in the heat of the General Election campaign after Labour leader Jeremy Corbyn suggested he would be prepared to turn down any Nato request for reinforcements.
The Labour leader said "at the end of the day wars are not solved by the presence of foreign troops" as he called for a political solution to the violence in the war-torn nation, while vowing to "look at" any request.
A Ministry of Defence spokesman said: "The UK keeps its contribution in Afghanistan under regular review to ensure it remains suited for the needs of the mission."
A Nato official said: "Nato regularly asks allies and partners to contribute forces for our missions and operations, for instance in Afghanistan and Kosovo.
"These requests are not targeted at only one nation, but are part of our force generation process which concerns all allies and partners.
"As regards Afghanistan, it's premature to discuss specific figures, as Nato leaders will discuss the mission at the May 25 meeting, with a further discussion on details by defence ministers in June."