According to online daily El Confidencial Digital, the habitual bargaining between Aspen and the Ministry of Health has taken a turn for the worse.
The South African manufacturer of generic medicines is currently undergoing a rapid expansion in international markets.
The company is allegedly insisting on massive price increases for a number of drugs but the Ministry has flatly refused.
Sources close to the negotiations reportedly told El Confidencial that the company might refuse to continue supplying the Spanish market in the next few weeks because of lack of profitability.
Spanish law, however, states that companies must continue to supply pharmacies or run the risk of incurring penalties.
Prices for medicines in Spain are usually set after a deal is struck between the government and pharmaceutical manufacturers.
"The companies speak with the Ministry of Health and they ask for the green light to sell a drug at a given price. Then the Ministry strives to set a lower or higher fixed price depending on the cost of production and the drug's therapeutic importance," a source reportedly told the website.
They added: "If they don't agree with the decision they can take it to a tribunal. They can file a claim and see how it's resolved. Otherwise they're obliged by law to supply pharmacies."
Five drugs sold in Spain are said to be at the centre of the squabble.
One of them is Melphalan Aspen, an ovarian cancer treatment which Aspen wants to sell for €150 ($205) per package – a 1000 percent increase on its current price of €15.25.
And Aspen purportedly wants to sell 2mg Leukeran (Chlorambucil), a leukaemia treatment, for €100 instead of €2.16 – a 4,000 percent price rise.
Other drugs being haggled over include Mercaptopurine Aspen and Thioguanine Aspen (both leukaemia treatments), plus Busulfan Aspen, used to treat blood disorders.
Aspen, which is partially owned by so-called 'big pharma' giant GlaxoSmithKline, reportedly declined to comment.