NSW TrainLink will begin operating two additional return services between Singleton and Newcastle each day from January 5 next year.

One of the new services will depart Singleton at 3.34pm each day, while the other will depart Singleton at 9.34pm on weekdays and 9.20pm on weekends.

The additions enable a later train back to Singleton from Newcastle, which will depart at 8.24pm on weekdays and 8.10pm on weekends.

The other service back from Newcastle will depart at 2.24pm each day.

Minister for Regional Transport Paul Toole and Upper Hunter MP Michael Johnsen confirmed the operating times at Singleton train station on Thursday afternoon.

"We are delivering on our election commitment and we have made sure the trains will hit the tracks from January 5," Mr Toole said.

"These new services will give customers more flexibility, greater choice and better connections when planning trips to health, education and leisure hubs in the likes of Newcastle, Maitland and Sydney."

Mr Johnsen committed to the extra services in February, but the number of trains and times they would run had been up in the air.

The Nationals MP also recently quashed doubts about the services beginning as planned in early 2020.

He said on Thursday the trains would operate under a year-long trial and it was essential the public got on board.

"It's your turn to show your support for these services so you can enjoy them in the long term," he said.

"The timing of the new services will deliver a more even spread of trains across the day, which means you can choose to spend just a morning or afternoon at your destination.

"This means Singleton locals can head to Newcastle for a day at the beach and return home in the early afternoon, while tourists will have more opportunities to discover what Singleton has to offer with its rolling hills, wineries and heritage walks."

Lochnivar, Greta and Branxton stations will also benefit from the extra trains.

Public transport advocacy group Two More Trains for Singleton has, as its name suggests, been campaigning for the extra services since 2008.

Spokesman Martin Fallding said the additional trains would make "an enormous amount of difference".

"It's extremely heartening that common sense solutions to transport problems can actually happen," he said.

"It's very exciting.

"The new services are the first step towards achieving the community desire for a two-hourly passenger train service to the town by 2030."

Singleton mayor Sue Moore thanked the group's members for the "countless meetings, letters and petitions over the years".

"It's now up to us in the community to take advantage of their hard work and use these services to make sure they not only continue, but that we might even continue to grow our passenger timetable," she said

The Herald revealed earlier this month how 50,000 extra passengers had used the Hunter line between March and August compared to the corresponding period last year.

Opal data suggests more than a million passengers will use the line in 2019.