The Rail Tram and Bus Union has planned a strike until 5am on Tuesday. Light rail and ferries are due to run as normal on Monday.

The union issued a statement on Monday advising there would also be an indefinite ban on logging into bus driver consoles after the strike ends in the early hours of Tuesday.

"It is the unions understanding that this action will not allow the Opal card readers to operate," the statement said.

"The RTBU apologies for any inconvenience to commuters and would prefer to see a resolution to the bargaining stalemate before continuing any industrial action."

Services operated by Hunter Valley Buses, Rover Motors and Port Stephens Coaches are not part of the industrial action and are expected to run as scheduled during the strike.

A Transport for NSW spokesperson urged customers to plan their commute, use alternative options and allow extra time.

"As Monday's industrial action will affect travel for many of our bus customers, we ask them to be prepared by checking the public transport apps and considering any alternative travel options that best suit their needs," the spokesperson said.

"While some bus services provided by other operators will still run as scheduled throughout the day, we understand the situation is frustrating for our customers.

"The reduced number of local bus services during this 24-hour period means other modes of public transport may be busier than normal, so please plan ahead."

The strike stems from negotiations on proposed enterprise agreements between Keolis Downer and workers.

Drivers are calling for a seven per cent pay increase over two years, rather than four years, in line with rising cost-of-living pressures.

Keolis Downer has said it will continue to negotiate in good faith, but union officials last week described their demands as "a fair ask".

"All this could be avoided if Keolis Downer would budge from the original insufficient offer made to drivers, which would see their wages go backwards," RTBU NSW tram and bus division president Daniel Jaggers said last week. "The private operator's solution was to then tell members they could earn more if they worked more - what an insult."

Transport for NSW identified the altered public routes as 11, 12, 13, 14, 21, 22, 23, 24, 25, 26, 27, 28, 29, 41, 42, 43, 44, 46, 47 and 48.

Most of the services caught in the fray are school runs. They include 500, 501, 502, 504, 507, 508, 522, 526, 549, 550, 551, 563, 570, 700, 701, 702, 704, 705, 706, 707, 708, 710, 711, 712, 714, 715, 718, 719, 720, 721, 723, 724, 725, 726, 727, 728, 729, 730, 731, 732, 733, 734, 735, 736, 739, 741, 743, 744, 747, 748, 749, 751, 753, 755, 756, 757, 758, 760, 761, 763, 765, 767, 768, 770, 771, 772, 773, 774, 775, 776, 778, 779, 780, 781, 782, 783, 786, 789, 790, 791, 792, 793, 794, 796, 797, 798, 799, 800, 801, 802, 804, 806, 808, 809, 810, 811, 812, 813, 814, 815, 816, 817, 818, 819, 820, 822, 823, 824, 825, 826, 829, 830, 831, 832, 833, 834, 835, 836, 837, 838, 839, 840, 841, 842, 844, 845, 846, 847, 848, 849, 851, 852, 853, 855, 856, 857, 858, 859, 860, 861, 862, 863, 864, 865, 867, 868, 869 and 870.