Nightrider buses are to run on the weekends of December 6 and 7, 13 and 14, 20 and 21 and on New Year's Eve and in the early hours of January 1.

If past usage patterns are any indication, between one-third and half of the patrons will use the service on the night of December 31 and early on January 1.

When the Nightrider service was trialled over three months in 2010-11, fares to South Canberra, Tuggeranong, Belconnen and Gungahlin were $10 a person. A $5 fare was charged for a Kingston, Manuka and Civic loop that operated every 30 minutes.

Attendances were disappointing and taxpayers ended up forking out $157 per passenger per trip.

A subsequent TAMS evaluation ruled this ''could not be seen to be cost-effective'' and said the final cost over the three months had come to $268,704. Critics accused TAMS of spending too little to promote a service which only carried 1716 passengers over the entire summer. Almost a third, 678, had travelled on New Year's Eve at an average cost to taxpayers of $22.33 per head.

The Nightrider service reverted to its one-month format in December 2011 and timetables were tweaked to make them more responsive to public demand. Other changes included a decision to spend $60,000 marketing the service and scrapping the $10 fare in favour of a $5 maximum. Partygoers responded with 2608 people using the bus compared to just 979 in December the previous year.

December 2012 recorded a slight fall in patronage with 2460 passengers for the month. More than half, or 1246, travelled on New Year's Eve.

It is believed the average cost per patron came to about $30.

Territory and Municipal Services Minister Shane Rattenbury said the decision to trial a free Nightrider bus service was an attempt to increase patronage.

Besides removing the temptation to drink and drive, the service has been linked to reductions in arrests in the centre of the city during the ''drinking season'', greater public safety and as a way of introducing people who would not normally use public transport to what is available.

''Nightrider is an important part of the government's transport services as a convenient option for people to get home on public transport late at night (and) it is also an important safety initiative providing alternative transport to people who have been drinking,'' he said. ''This is the first time Nightrider has been free; we hope to attract new riders to the service and expect higher levels of patronage. ACTION will have a limited amount of standby services to cater for a higher volume of riders. With the money you save on transport you can buy yourself a kebab. Just make sure you finish it before boarding the bus.''