Nokia has started deliveries of its E61 business phone with full keyboard, a model directly competing with RIM's BlackBerry device, the world's largest handset maker said on Wednesday.

The E70 model, with a 2 megapixel camera, is expected to start shipping later in May. The first E-series phone, the E60, went on sale in April.

The three E-series phones, aimed at business users, and three of Nokia's flagship multimedia N-series handsets missed their original target shipping dates due to software- related problems.

Nokia last October unveiled the new business phone line-up -- part of the Finnish company's plan to win more of the potentially lucrative corporate market -- and said at the time that it would start shipments in the January-March quarter.