Results of a tendering competition for 10% of Dublin Bus routes are due to be announced by the National Transport Authority.
Dublin Bus itself is believed to have applied for the franchise, as well as a number of British bus companies.
The 23 routes are all serving outer suburbs of the greater Dublin area and none go into the city centre.
Among them are the 185, which connects Bray with Newtownmountkennedy, the 76a, which connects Blanchardstown and Tallaght shopping centres, and the 220, which travels from Ballymun to Mulhuddart.
The NTA has previously denied that if the franchise is awarded to a commercial operator it would amount to privatisation.
The authority points out it would retain ownership of the bus fleet and revenue, but would pay an operator to run the routes in the same way that Transport Infrastructure Ireland controls operation of the Luas.
If a commercial bid is successful, this is not expected to provoke a reaction from unions such as SIPTU and the NBRU.
Both unions reached an agreement with the Department of Transport following industrial action over the threat of privatisation two years ago.
It is understood that the growth in passenger numbers in recent years means that no Dublin Bus employees will face redundancy or be forced to move to any new operator.
Whoever wins the franchise will also have to maintain existing bus services for the public.
The routes in question are:
17 Rialto to Blackrock
17a Blanchardstown Centre to Kilbarrack
18 Palmerstown(Old Lucan Road)to Sandymount
33a Swords to Balbriggan
33b Swords to Portrane
45a Dún Laoghaire (Rail Station)to Ballywaltrim
59 Dún Laoghaire to Mackintosh Park
63 Dún Laoghaire to Kilternan
75 The Square Tallaght to Dún Laoghaire
76 Chapelizod to Tallaght (The Square)
76a Blanchardstown Centre to Tallaght (The Square)
102 Sutton station to Dublin Airport
04 Clontarf Road (Conquer Hill) to Santry (Shanard Road)
111 Loughlinstown Park to Dún Laoghaire
114 Ticknock to Blackrock Station
161 Dundrum Luas Station to Rockbrook
184 Bray Rail station to Newtownmountkennedy
185 Bray Railstation to Shop River (Enniskerry)
220 Ballymun (Shangan Road) to Lady's Well Road
236 Blanchardstown Centre to Damastown
238 Tyrrelstown to Lady's Well Road
239 Blanchardstown Centre to Liffey Valley Shopping Centre
270 Blanchardstown Centre to Dunboyne