Spanish fashion retailer Inditex on Friday said that its former CEO Jose Maria Castellano has resigned as deputy chairman and as a member of the board.

In a short statement the company, which owns the Zara fashion chain, said the resignation was due to "personal reasons."

However, Spanish press reports speculated that the reason for his departure was "irreconcilable differences" with Pablo Isla who took over from Castellano as CEO.

Other press reports also suggested that a row over a failed attempt by Inditex chairman Amancio Ortega to buy a stake in energy firm Union Fenosa SA that led Castellano to quit the company. He was not invited to join the group of investors who put in the offer.

Castellano told El Mundo: "When I learned about the deal, I noticed that some aspects were not well thought-out, so I doubted it could succeed. When they called me to join the deal, it was too late to put it straight and I didn't want to take part."

Castellano and Ortega worked together for over 20 years, building Inditex to an international retail powerhouse. On Wednesday, Inditex posted a 29 per cent rise in first-half net profit and improved its full-year outlook.