Merz will be "received by Prime Minister Keir Starmer," government spokesman Stefan Meyer said.
The two will sign a "friendship agreement" covering cooperation in foreign policy and security, he added, quoted by AFP.
Germany and Britain, both allies of Ukraine, are racing to rearm in the face of a hostile Russia and amid fears that US President Donald Trump is not committed to defending European NATO partners.
The agreement will also include measures to stimulate economic growth and promote "closer contacts between the citizens" of the two countries, Maier said.
In October last year, Britain and Germany signed a "historic" defense pact and have since announced several joint initiatives, including the development of strike missiles.
Merz's trip will follow French President Emmanuel Macron's state visit to the UK this week, which is the first visit by an EU head of state since Britain's exit from the bloc. | BGNES