GAB Robins chief executive John Castagno and UK managing director Derek Coles have stepped down as part of an internal management reshuffle at the loss adjuster.

Castagno's resignation will take effect from November, while Coles will join the North American branch of the company to work with Rob Meyers, president of the insurance company services division.

The head of the firm's Australasian operations, Kieran Rigby, will now become chief executive. GAB does not plan to replace Coles.

Rigby's brief is to continue the streamlining of operations at GAB Robins with the view of using technology to increase cost-efficiency.

He will become chief operating officer of the international group, second-in-command to Philippe Bes, GAB executive vice president and chief operating officer.

In a personal statement Castagno said he sought a fresh challenge and intended to continue to work in the insurance industry.

Earlier this year Castagno and Coles were said to be the main instigators of a potential management buy-out that was later refuted by GAB.

Bes categorically denied any plans to sell GAB Robins in the immediate future, saying it was the will of the shareholders that the company continued to operate in the market.