Online retailer CatchOfTheDay has rebranded itself Catch and relaunched as a marketplace for other sellers in a move that puts it in direct competition with US giant Amazon.

Since Amazon confirmed it will roll out its full online offering in Australia, shares of major retailers including Kmart, Target owner Wesfarmers, JB Hi-Fi, Harvey Norman and Myer have been battered.

Analysts have been warning that the nation's retail sector is in for a major shake up as seen in the US and UK where the eCommerce behemoth's low prices and quick deliveries drove many out of business.

But Catch Group chief executive Nati Harpaz is optimistic that there is room for smaller online players and, in a surprise move, has opened up the site from being purely a seller of brands to being a platform for other retailers.