Saudi Arabia and its allies have been urged to keep ports open to allow the flow of aid into Yemen amid concerns the blockade could be reimposed.
International Development Secretary Penny Mordaunt promised £1.3 million and British expertise to help ensure that arms destined for rebel forces are not shipped into Yemen alongside vitally needed aid.
A window allowing aid into the key port Hodeidah is due to close on January 19 but Ms Mordaunt said unrestricted access must be maintained.
The Saudi-led coalition originally imposed a blockade amid concerns about the flow of arms to Houthi rebels.
To address those concerns the UK is providing £1.3 million to the UN's Verification and Inspection Mechanism (UNVIM) to provide assurance against weapons smuggling.
British experts have been seconded to UNVIM in Djibouti to assist with the inspections process.
Ms Mordaunt, who visited the region in December, said: "I heard about some of the heartbreaking tragedies suffered by Yemenis when I met with refugees and international aid workers last month.
"I am pleased restrictions on access have since been eased at the ports of Hodeidah and Saleef, allowing 19 ships to deliver food and critical fuel.
"This is already saving lives by ensuring hospitals can continue delivering essential medical care, water can be pumped into major cities, grain can continue to be milled into flour and food transported to those most in need.
"But the situation in Yemen remains dire and will deteriorate rapidly unless unhindered access is maintained, especially to the north of the country.
?"With Yemen importing 90% of its food and fuel, it's essential that Hodeidah and Saleef ports remain fully open to help millions of people who are at risk of starving to death.
"We recognise Saudi Arabia's legitimate security concerns and will continue to provide support to prevent illegal arms smuggling into Yemen - this does not require stopping humanitarian and commercial supplies from reaching those in need."