CORRECTED-Britain's competition watchdog probes Iberdrola merger with NWEN

Corrects to say deadline is February 12 (not March 27), adds that March 27 is deadline for phase 1 decision, in paragraph 2

LONDON, Jan 29 (Reuters) - Britain's Competition and Markets Authority said on Wednesday it was weighing whether a merger of Spain's Iberdrola IBE.MC and NWEN Ltd could reduce competition in the energy sector, and make it tougher for market regulators to keep track of pricing.

The CMA has set a deadline of February 12 for submissions by interested parties to phase 1 of its merger enquiry, and a deadline of 27 March for the phase 1 decision.