Labour leadership contender Ed Balls is due to visit the Hove and Portslade border at lunchtime.
The former Schools Secretary is expected to visit a Keep the Post Public campaign event outside the Royal Mail delivery office in Boundary Road, Hove.
The campaign is scheduled to set up its stall at 1pm with Mr Balls expected to arrive at 1.45pm with Simon Burgess.
Mr Burgess is a former Labour leader of Brighton and Hove City Council and ran for Parliament in Brighton Kemptown at the general election in May. The seat was won by Simon Kirby, the Conservative.
The post office campaigners will be asking people to sign a petition opposing the planned privatisation of the Royal Mail.