Justine Greening has been appointed education secretary and minister for women and equalities, Number 10 said.
She was formerly the secretary of state for international development.
She told reporters it was her "perfect job" as she left No 10.
Justine Greening, the secretary of state for international development, has arrived at Number 10, as Theresa May's Cabinet reshuffle continues.
An announcement on her position in the Cabinet is expected soon.
Asked if she might fill the health or education posts, Ms Greening said "it's not up to me".
A team of more than 60 search and rescue responders and medical experts has been deployed to support the relief effort in Nepal, International Development Secretary Justine Greening said.
A Department for International Development-chartered flight is leaving London tonight for Kathmandu, carrying seven UK International Search and Rescue crews, four search and rescue dogs, a medical support team and a hazardous materials specialist.
They will take with them more than 11 tonnes of kit, including torches, axes, rope, search cameras, stretchers and tents.
Also on board will be trauma medics travelling as part of a DFID-deployed UK Med team and a five-strong Foreign Office Rapid Deployment Team.
ITV News' Political Correspondent Lewis Vaughan Jones reports:
The Government has announced the four charities that will share £3 million to provide humanitarian aid in northern Iraq.
International Development Secretary Justine Greening announced the charities are: Mercy Corps, Save the Children, the International Rescue Committee and Action Against Hunger.
The funding is being provided through her department's Rapid Response Facility, which fast-tracks money to charities in the event of a humanitarian crisis.
It is part of the £8 million Iraq aid package released by the Government on Thursday.
Britain is to contribute another £15 million towards helping the Philippines recover from the devastation wreaked by typhoon Haiyan, International Development Secretary Justine Greening has announced.
The aid boost - which takes the total UK contribution to £75 million - will help fund efforts to rebuild homes and get people back into jobs.
One of the biggest storms on record, Haiyan killed at least 5,700, destroyed or damaged the homes of six million people and directly affected another nine million.
Among reconstruction efforts being supported by the aid is the rebuilding of homes, schools and hospitals, the restoration of public services and employment programmes.
Efforts to revive the devastated rural economy include reconstructing irrigation systems, replanting coconut trees and re-establishing fisheries.
An RAF C-17 Globemaster plane has delivered further emergency supplies and humanitarian aid to typhoon-hit areas of the Philippines.
International Development Secretary Justine Greening joined the crew from Malaysia to Cebu in the Philippines to oversee the process.
The RAF said the C-17 Globemaster's ability to fly long distances and land in remote regions makes it a "premier transporter" for humanitarian missions.
HMS Daring will "help get donations to those who need it" in typhoon-hit areas of the Philippines, International Development Secretary Justine Greening has said.
She wrote on Twitter:
International Development Secretary Justine Greening said there has been "a tremendous response" to the disaster in the Philippines, "these appeals underline just how serious the situation is".
Ms Greening said: "Backing the UN and Red Cross appeals will ensure the relief effort is properly co-ordinated and much-needed assistance gets to those who need it.
"I hope other countries will be joining us to give the Philippines the support it needs."
The Government has begun implementing a £6 million "rapid response" to the crisis in the Philippines, the International Development Secretary has said.
The British response is being co-ordinated with aid agencies that already have a presence "on the ground", the minister told ITV's Daybreak.
"We've also flown out two NHS experts, and I think what we'll now do is quickly assess the scale of the needs," she said.
The Government has pledged a further £2 million in aid for Syria's children, many of whom "have lost absolutely everything".
International Development Secretary Justine Greening told Daybreak the money will be focused on the children in Unicef-run refugee camps in Iraq.
Ms Greening said: "This money will first of all help provide safe zones for them so we can actually make sure they are being taken care of, secondly trauma support and counselling, and where they have medical needs they need to get care for that as well."