Google has had its proposed $90m settlement in a click fraud case approved by a US state judge.

The agreement came after years of wrangling over legal action first brought by Lane's Gifts and Collectables in February 2005, and later changed to a class action suit comprising more than 70 objections.

Google had been accused by several companies of not doing enough to protect advertisers from 'click fraud' in which advertisers are falsely charged for channelling clients to their websites.

The search firm charges advertisers a fee every time a user clicks on an ad displayed on the company's website.

Google has since improved security and brought in new features which ensure that advertisers get more details regarding their Google ad accounts and any invalid click activity.

Under terms of the settlement Google will have to give advertising credits worth $4.50 for every $1,000 spent on advertising on its website.

Miller County Circuit Judge Joe Griffin approved the settlement as "fair, reasonable and adequate".

Yahoo settled a similar case brought in California earlier this year.