SINGAPORE - Households can expect higher electricity and lower gas bills for the next three months.

Electricity tariffs are set to rise by an average of 3.5 per cent in the first quarter of next year, SP Group said on Monday (Dec 30).

For the period from Jan 1 to March 31, electricity tariffs will increase by 0.81 cents per kilowatt hour (kwh) compared with the previous quarter.

Excluding the goods and services tax (GST), this translates to a rise from 23.43 cents per kwh to 24.24 cents per kwh for households powered by SP Group.

This is the highest it has been since the period from October to December 2014, when it was 25.28 cents before GST.

It exceeds the rate of 24.22 cents from July to September this year, the previous highest rate.

SP Group said that the increase is mainly due to higher energy cost compared with the previous quarter.

The average monthly electricity bill for families living in four-room Housing Board flats will rise by $2.76, excluding GST.

City Gas also announced on Monday that gas prices will be falling.

The gas tariff for households will dip by 4.22 per cent, which means they will pay 17.23 cents per kwh in the first quarter of the year, down from 17.99 cents per kwh, before GST.

City Gas said that the lower gas prices are due to a decline in fuel costs compared with the previous quarter.

When asked why electricity prices are rising and gas prices falling, an Energy Market Authority (EMA) spokesman said: "The difference between the electricity and town gas tariffs is mainly due to the different fuel types used and their prices moving in different directions."

Both SP Group and City Gas review tariffs quarterly, based on guidelines set by the EMA, which approves the new pricing.