The publisher plans to update the sites of its biggest brands, including Good Housekeeping, Cosmopolitan and Country Living, within the next six months and the rest of the consumer websites will follow.
Each of the free-to-access sites will offer more opportunities for user interaction, alongside a mixture of magazine and web-only editorial and more archive material.
Management of the sites will be integrated with that of the magazines and each title's editor will oversee content on both platforms.
Duncan Edwards, NatMags chief executive, said: "Our sites currently offer a thin product that doesn't really add much value beyond driving subscriptions and merchandise sales.
"Being a magazine reader is like being a member of a club and we want the sites to reflect that with compelling content, strong community tools and specialist services."
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the Forum.