The website, which is believed to be the largest social networking site of its kind in the UK, said the funding would be used to bolster its online service to hard to reach community sectors and provide peer-to-peer and expert advice on parenting issues.
Netmums, which has around 750,000 unique monthly users, said the DCSF's decision to invest in the site was different from the use of traditional government-run websites to reach particular sectors of the population.
The site has worked with Unite/Community Practitioners and Health Visitors Association for three years, and will now extend the relationship to finding counsellors, health visitors and representatives from organisations such as Women's Aid.
Netmums said the funding would also be used for generating self-help materials for mums and creating online lifestyle courses.
Cheryll Adams, acting lead professional officer at Unite/CPHVA, said: "We have been working informally with Netmums for over three years, supporting their great work and providing consultation.
"The mothers who choose to use anonymous channels such as Netmums to disclose difficulties are often those who our health visitors struggle to identify and help."
Netmums is also supported by BT, Early Learning Centre and children's TV channel Nick Jr.