British Prime Minister Theresa May said yesterday she would announce changes to her ministerial team soon, with media reports saying her foreign, finance, interior and Brexit ministers would keep their jobs in a reshuffle starting today.

After running a poorly-received campaign at a national election last year that badly damaged her authority, May is leading a delicately balanced minority government tasked with delivering Britain's exit from the European Union. She is also under pressure to tackle a range of domestic policy problems.

May said ministerial changes were necessary following the departure of her long-standing ally and de-facto deputy prime minister Damian Green, who she forced to resign in December after he made misleading statements about pornography found on an office computer.

"Obviously, Damian Green's departure before Christmas means that some changes do have to be made, and I will be making some changes," she told the BBC in an interview filmed on Saturday for broadcast yesterday.

May said the reshuffle would come soon, but did not give any further details.

The Sunday Times said foreign minister Boris Johnson, finance minister Philip Hammond, interior minister Amber Rudd and Brexit minister David Davis would not lose their jobs in the reshuffle. The report did not cite its sources.

May is also expected to announce a new first secretary of state to replace Green - an important post with responsibility for maintaining unity in a cabinet still divided over the best approach to Brexit.