UPDATE 1-GMB union to strike over Centrica's British Gas 'fire and rehire' threats

(Adds Centrica’s statement and more details from GMB’s statement)

Dec 17 (Reuters) - Members of the Britain’s GMB union have voted for industrial action in January against Centrica Plc’s British Gas after the utility refused to remove “fire and rehire” threats to its workforce, the union said on Thursday.

"GMB members at British Gas vote 89% for strike action as Centrica refuse to remove their fire & rehire threats," the union said in a statement here.

In June, Centrica, Britain’s largest energy supplier, said it planned to cut around 5,000 jobs, almost 20% of its global workforce, and change the terms of worker contracts, as the utility deepens its restructuring efforts in the wake of the COVID-19 pandemic.

The “fire and rehire” proposal would allow it to terminate existing contracts and offer fresh terms, known as a section 188 notice. Centrica has described the plans as an “insurance policy” if talks with unions fall apart.

Centrica said on Thursday the GMB union did not have a “strong mandate” for the strike and noted other unions such as UNISON and Unite had accepted the company’s final offer.

“As only 52.5% of GMB members who could vote, voted to support industrial action, we do not believe the GMB leadership has a strong mandate for strike action,” it said in a statement.

Centrica has said it faces difficult conditions, including losing market share to smaller competitors, low oil and gas prices and a regulatory price cap, which have squeezed profitability.

GMB said British Gas has set Dec. 23 as the new deadline for staff to accept the planned cuts or lose pay and protections ahead of being sacked.

“GMB shop stewards and officials will meet to consider and assess the ballot result and the nature of the industrial action and the dates for action - initially across January,” GMB union said in a statement.

Centrica employs around 27,000 people, with around 20,000 based in Britain. GMB represents than 7,500 of Centrica’s employees. (Reporting by Aakriti Bhalla in Bengaluru; editing by Richard Pullin)