Google has renewed its assault on the corporate market with the launch of an enterprise search service.

Google Site Search allows users to run a hosted version of Google's software to index and provide search capabilities for company websites.

The service offers the ability to "bias" searches towards specific dates, a customisable synonym directory and an improved indexing system.

Google said that the aim is to improve on the basic search features provided on most commercial sites.

"Website owners typically invest in good content, search optimisation and advertising to attract customers, but often lack a quality search experience once customers arrive," said Dave Girouard, president of enterprise at Google.

"With Google Site Search websites can immediately increase customer satisfaction as they are improving their business results."

The service is hosted by Google and costs $100 annually for up to 5,000 pages.

Google has also announced a new 'makeover' competition for enterprise site owners. Winners of the Google Website Workout will receive personal help and advice from Google consultants in redesigning and improving the effectiveness of their sites.

Site administrators have until 17 June to answer a series of written questions about why their site deserves a "Google workout".

Four winning sites will be chosen by the company to receive the Google makeover and optimisation service.

The contest is part of a promotion for Google Website Optimiser, a tool designed to help businesses increase the effectiveness of commercial sites.