Toshiba, the Japanese electronics group, has signed a deal to secure supplies of rare metals for its nuclear power business from Kazatomprom, the state-owned Kazakh nuclear company, in the latest sign of strong demand for such commodities.

The agreement expands on an existing deal under which Kazatomprom supplies uranium for Toshiba-built nuclear plants. Kazatom-prom, the world's third biggest uranium producer, bought a 10 per cent stake in Toshiba's nuclear subsidiary, US-based Westinghouse, for $540m last year as part of a strategy to gain access to advanced nuclear power technology.