Frankfurt, Oct. 8 (Reuters): German carmaker Volkswagen has offered Porsche to help it secure another 3.4 per cent stake via a capital increase, cementing the two firms' co-operation, according to media reports on Saturday.

Luxury carmaker Porsche is already in the process of securing an 18.53 per cent stake in Europe's largest carmaker.

Weekly magazine Der Spiegel, said in a report to be published on Monday, Volkswagen CEO Bern Pischetsrieder had offered Stuttgart-based Porsche to arrange a capital increase in which other shareholders would be excluded from participating.