A month-long campaign by Walsh Trott Chick Smith and Naked, using the slogan "Public services all in one place", will be followed by a similar burst this autumn.
The budget will be split between national press, radio, online, London buses, trucks and plastic milk bottles in Sainsbury's and Tesco.
Directgov was launched in 2004 and allows people to use services run by 11 government departments, which share the cost. Services include social security, finding a childminder and renewing car tax.
Alex Butler, the strategy and marketing director of Directgov, said: "We have deliberately held back until this stage. Being the Government, we had to make sure everything was right. It took this amount of time to get the product right."