A union representing many of Germany's train drivers started a nearly three-day strike early Wednesday in a bitter dispute with the country's state-owned main railway operator over working hours and pay.

Train travel across the country and in many cities came to a near standstill with commuters and other travellers struggling to find alternatives involving long-distance bus or car travel or flights.

State-owned Deutsche Bahn said only around 20% of its long-distance trains were running and many regional and commuter trains in cities like Berlin were also not in operation.

It comes as disgruntled farmers blocked motorway slip roads and snarled traffic elsewhere with their tractors as part of a separate protest against a government plan to scrap tax breaks on diesel used in agriculture.

Images shared on social media showed horrendous traffic jams clogging up roads in several German cities, and a line of dozens of tractors blocked the main avenue leading to the Brandenburg Gate.

'The strike by the train drivers' union GDL has had a massive impact on train services in Germany,' said Deutsche Bahn spokeswoman Anja Broeker. 'We regret the restrictions and hope that many people who were unable to reschedule their journey will get to their destination.'