One of the main unions representing the U.K. offshore oil and gas industry responded angrily Wednesday to plans from oil giant BP PLC (BP) and its contractors to reduce wages in order to cut costs.

A BP spokeswoman said the changes still honor existing pay agreements and cutting costs is important for the future of the business.

"Our North Sea business is not sustainable at current oil and gas prices. We need to take action to protect activity levels and jobs," she said.

But Willie Wallace, regional officer for Unite in Aberdeen, Scotland, said oil companies had "conveniently forgotten the record profits they made last year on the back of high oil prices and now that the oil price has fallen they want to attack our members' well earned wages."

"BP are looking to make significant savings in the North Sea and they are asking our members to bear the brunt of the cost savings" through measures including wage cuts, said Wallace. "Our members offshore have already reacted with anger at the level of the proposed cuts."

The BP spokeswoman said that over the years, BP had paid certain discretionary payments. "In the past, all OCA workers would get paid one hour overtime whether they worked it or not ... now we will only pay for overtime or a night shift when it is actually worked," she said.

Workers will meet in the next few weeks to determine their response to the plan, the Unite union said Wednesday.

The cuts will affect around 800 workers for contractors AMEC PLC (AMEC.LN), John Wood Group PLC (WG.LN), Sparrows Offshore, RBG, BIS Salamis, PSN and Cape PLC (CIU.LN), Wallace said. The contractors have commenced a 90-day consultation with their workers on the proposals, he added.

Construction projects at power plants, chemical plants, refineries and gas import terminals were affected last week when more than 4,000 contractors staged unofficial strike action to protest job losses at Total SA's (TOT) Lindsey oil refinery in eastern England.

Company Web site: http://www.unitetheunion.com

-By James Herron, Dow Jones Newswires; +44 (0)20 7842 9317; james.herron@dowjones.com