The NSW government has expanded its Energy Switch service to include gas, saying the program has already saved households more than $400 a year on average on their electricity bills.

“Winter is here, so now is the time to compare gas and electricity plans. It takes only minutes but could save hundreds of dollars a year,” Premier Gladys Berejiklian said on Sunday when launching the service’s expansion.

The service allows households to find the cheapest available energy plans and then switch providers easily online or via the phone.

Ms Berejiklian and Energy Minister Matt Kean said in a statement about 7000 households have already switched electricity providers, bringing close to $3 million in annual savings since the free service launched last year.