David Cameron will try to inject new momentum into international efforts to end the bitter Syrian civil war when he joins world leaders at the United Nations in New York at the weekend.
The Prime Minister flies out to the 70th anniversary meeting of UN General Assembly on Sunday with the fall-out from the bloody four year conflict at the top of the agenda.
"The PM's priorities for the UN General Assembly are to be working with other leaders to engage on issues abroad that matter to our security at home," the Prime Minister's official spokeswoman said.
Around 140 heads of state and heads of government are expected at the event including Russian president Vladimir Putin and China's president Xi Jinping as well as US president Barack Obama.
The migrant crisis - which has seen Europe overwhelmed by tens of thousands of people fleeing the fighting in Syria and other conflict zones around the world - is expected to ensure much of the focus is directed towards the region.
British officials said that as well as seeking to address the challenge posed by the mass movement of such large numbers, Mr Cameron will highlight the need to tackle the continuing threat from Islamic State while renewing efforts to find a diplomatic solution in Syria.
The Prime Minister will also speak on the UN sustainable development goals to help the lift the world's poorest countries out of poverty as well as the need for an "ambitious" agreement at international climate change talks in Paris in December.
"In particular he wants to focus on the migration situation, the situation in Syria, how the world can take forward the sustainable development goals and make sure that no one is left behind," his spokeswoman said.
Ahead of Mr Cameron's visit, International Development Secretary Justine Greening announced more than £50 million in additional funding for programmes aimed at helping women in girls in the developing world.
They include projects to tackle sexual violence against teenage girls in Ghana, help women in Nepal find jobs and end discriminatory laws in countries around the world.
"For far too long girls and women have been invisible outside of the home. They have been excluded not just from the jobs market but from owning land, from registering a business and from accessing a bank account," Ms Greening said.
"I firmly believe that improving the lives of girls and women is one of the smartest investments we can make, which is why Britain will continue to lead from the front on this."