LONDON (Reuters) - British Airways' <BAY.L> main cabin crew union, Unite, said on Tuesday its members had rejected a revised airline pay offer, in a long-running dispute over pay and staffing levels which has cost the carrier millions.

The union, which represents 90 percent of BA's 12,000 cabin crew, said 67 percent of its members had voted against accepting the offer.

"The union will meet cabin crew representatives this afternoon to discuss the next steps," a Unite spokesman said.

The dispute, which began last November when BA announced it was cutting crew pay and was reducing staffing, has cost the airline 150 million pounds ($227.9 million) in a series of strikes.

The offer included two years of guaranteed rises in basic salary from February 2011 in addition to annual incremental pay increases.

($1=.6583 Pound)

(Reporting by Stefano Ambrogi; Editing by Keith Weir; Editing by Hans Peters)