Minister of finance Christian Gorke said the Brandenburg state must not be disadvantaged by the future budget savings of the European Union.
The state surrounds the German capital of Berlin and depends on EU funds.
Mr Gorke said: “As a land area we are dependent on funds from Brussels.”
Last year, Treasury figures revealed the UK paid about £13bn to the EU, around £200 per person, some of which then gets spent in the UK.
When the UK leaves the bloc, one of the key contributors along with Germany, France and the Netherlands, the EU will need to find budget savings.
Other countries in the bloc may be forced to cough up more cash to make up for the shortfall.
About half of the state of Brandeburg’s area is used for agriculture and roughly another third is covered by forests.
Every year, Brussels contributes around £304 million in direct payments to Brandenburg farmers and around £276 million to the allocation of structural funds.
Mr Gorke said: “Challenges for Brandenburg will not be smaller.”
The EU’s budget from 2020 onwards is currently being discussed and significant cuts are expected following the UK leaving the bloc.
President of the State Farmers’ Union, Henrik Wendorff, said: “We continue to need the aid.”
This week Brussels insisted the UK would have to pay double contributions to the EU when it quits the bloc.
The EU diplomat said they will demand budget payment linked to a transitional deal separately to the divorces payout.
Brussels is already demanding a bumper Brexit bill payout from the Britain, expected to be up to £90 billion, which it says is required to cover budget commitments the UK has already signed up to.