The money is aimed at victims of attacks by Boko Haram Islamist militants in north-eastern Nigeria. More than 1.5 million people are on the brink of famine in the area, aid agencies say.
International Development Minister Priti Patel said the Nigerian authorities needed to do more to defeat the extremists and to “secure the safety and well being of its own people”.
She also said other donors should increase their assistance.
On being asked if she was comfortable with a substantial cut in Britain’s humanitarian aid, Ms Patel replied that she did not see it as a cut because she had just announced more money for Nigeria.
“My job isn’t just to give aid and money… but also to get others to contribute as well.”
She said that other countries and development partners needed to share the aid burden.
“This is an international crisis… the international development community must come together. That’s other donor countries.”
North-east Nigeria has been devastated by Boko Haram since 2009, with more than 20,000 people killed and 8.5 million people in need of urgent support, according to the UK Department for International Development.