Germany launches on Monday a new flat-rate public transport ticket valid across the country, but the 49-euro ($54) price point has raised doubts about the pass's potential impact.

Touting the monthly pass as a "revolution", policymakers hope it will bring some relief for consumers amid soaring inflation, and encourage people to favor mass transit in the name of the environment.

The "Deutschlandticket" offers unlimited access to Germany's bus and metro systems, as well as local and regional trains — with only long-distance high-speed services not included.

Transport Minister Volker Wissing was quick to call the new initiative "the biggest public transport reform in German history", but the pass's success is far from assured.

The association of German transport companies (VDV) expects 16 million of the country's 84 million inhabitants to take up the offer. Roughly 750,000 tickets have been sold already, without counting people who will switch over from their current transport subscriptions.

How to finance the new policy was the subject of months of debate, delaying the roll-out of the ticket.

An agreement was reached between the federal government and Germany's states, which will both contribute 1.5 billion euros towards the ticket's financing to avoid adding to the national rail operator's debt pile.

The expenditure has come in for heavy criticism from the opposition, who argue the money could have been used to "improve and renovate rail infrastructure", in the words of conservative (CDU) parliamentarian Michael Donth.

Germany's rail network is indeed creaking, with investment needs totaling around 8.6 billion euros a year for the next 10 years, according to official estimates.

With services packed and facing regular technical problems, only 65.2 percent of long-distance trains arrived on time in 2022.

The issues on Germany's rail system were put on full display last summer when the government first experimented with a heavily discounted flat-rate ticket. Between June and August, locals were able to travel the length and breadth of the country for just nine euros a month.