A group of travel websites including Expedia and Microsoft are urging the Justice Department to halt Google’s proposed $700m acquisition of flight information company ITA Software.

Former chief of the anti-trust division of the US Department of Justice Thomas Barnett is serving as counsel for the group.

Members of the FairSearch.org coalition are Microsoft, TripAdvisor, Expedia, Kayak, and Hotwire. They say that the deal will give Google excessive control over the online travel sector and bring "consumers higher prices and less choice in travel."

Barnett told AFP that the combined entity will end up dominating the online travel search space.

Barnett said the Justice Department has the option to place restrictions on the deal to protect competition, but such a thing would be difficult to monitor or enforce, so the best option is to block the deal.

Barnett said, "In this case, the best answer really is to block the transaction."

Google said the deal is intended to improve services for customers with better tools for them to compare flight options and prices. It added that it has no plans to sell airline tickets or change airfare prices.

The Justice Department is reviewing the deal.