The cargo arrived in the capital Juba yesterday morning as high-stakes talks aimed at ending weeks of bloodshed finally began in Addis Ababa, Ethiopia.
Thousands have been killed in South Sudan and as many as 200,000 forced from their homes by fighting between troops loyal to president Salva Kiir and those backing his sacked deputy Riek Machar.
The emergency supplies, provided by Oxfam and funded by the International Development department, are in addition to the £12.5 million of emergency assistance from Department For International Development announced in December 2013 to provide clean water, health care and shelter.
The task is to try and stop a secondary health crisis from striking.
UK International Development Secretary Justine Greening said: "We continue to assess the situation on the ground and stand ready to deliver further humanitarian assistance."
Representatives of the warring factions are holding advanced peace talks for the first time since conflict began in the country on December 15.
The talks are focusing on a ceasefire and the release of political prisoners.
An immediate monitored ceasefire must be the top priority of negotiations between South Sudan's warring factions, according to the UK's Africa minister Mark Simmonds.
He said the humanitarian situation was of "grave concern" and urged the parties to show flexibility.