British Gas' owner Centrica has stressed that UK households could encounter more increases in their fuel bills due to higher wholesale gas prices.

The Financial Times has reported the company as saying that consumers are up against an average increase of £50 a year in the underlying cost of delivering gas and electricity.

"These movements reflect colder than usual weather in April following mild conditions in the first quarter and the impact of energy efficiency measures being undertaken by customers," Centrica told the news provider.

However, Centrica did not reveal specifically if or how it might potentially increase its prices of domestic gas and electricity supplies.

These warnings of a potential increase in Centrica's costs come after The Belfast Telegraph reported that gas consumers in Northern Ireland have been charged higher fees by Firmus than those living in cities.

The company is increasing its fees for rural domestic and business customers, while gas users in Greater Belfast are enjoying cheaper rates.