The Singapore prime minister's nephew said on Wednesday he had hired top British lawyer David Pannick to advise him on a contempt of court case at the heart of a feud among members of the city-state's first family.

Pannick, who counts Queen Elizabeth II and Saudi Arabia among his clients, is one of the lawyers who this week won a landmark case to overturn the British government's suspension of parliament in the weeks before the deadline to exit the EU.

"Over the past two years, my legal team has taken advice from David Pannick, a leading expert," the nephew, Li Shengwu, said in a Facebook post.