Marketing spend for this year will be increased to £42m from £35m, with a focus on direct marketing campaigns targeting current customers.
Egg's most popular product is its credit card, which attracted 171,000 new customers in the second quarter of 2004.
The company is planning to use a mixture of direct mail, online and press advertising to cross-sell its other financial products, such as personal loans or insurance, to credit-card holders.
Egg is also planning to repeat TV advertising, created by Mother, at the end of the year to increase brand awareness. It has set itself a target of 500,000 new customers by the end of the year.
The increased focus on marketing follows the online bank's half-year results, which revealed a UK operating profit of £34.5m.
However, Egg has been hit by a disastrous foray into France, where it made an operating loss of £32.2m for the first half of this year. It subsequently announced its withdrawal from the country.
Egg, currently owned by Prudential, is at the centre of a bidding war.
US credit card giant MBNA is favourite to secure a takeover.