A shift in motorist’s buying habits across Europe may lead to Opel adjusting production volumes at its Ruesselsheim plant in Germany.

According to union sources, Opel may cut production at its homeland plant by up to half from 123,000 to 68,000 vehicles per year.

"Opel continuously adjusts production. We want to further improve the capacity utilization of our plants. This of course also applies to Ruesselsheim," an Opel spokesman said, adding that the company does not publicly comment on details of its internal plans.

Opel builds its Insignia midsize car and Zafira minivan in Ruesselsheim, and these are the models that are falling in sales across the continent.

Sales of the Opel Zafira dropped by almost 40% to 29,220 last year while sales of the Insignia dropped by 6.8% to 67,053. The Grandland X, Opel’s large SUV whose 2018 sales were 74,299 is the vehicle that is taking up most of the slack but, this is built in PSA's plant in Sochaux, France.

The company aims to cut production from 42 to 35 from 42 vehicles per hour, having lowered the output to 42 vehicles only last month.

In May, Opel's labour leaders agreed with PSA management on an investment plan and job guarantees for German factories in return for wage concessions.

PSA Group bought Opel and its UK sister brand Vauxhall from General Motors last year in a $2.6 billion deal, saying it aimed to restore Opel to profitability by 2020.