CTC's Tom McClelland and Barry Flood joined other cycle campaigners in protesting against allowing taxis into bus lanes in Belfast.
Although not perfect, bus lanes provide priority and a lower-traffic environment for cyclists, but changes to the way taxis are licenced in Northern Ireland could mean many more vehicles using the routes.
Up to 2,000 more vehicles could use the routes if ministers approve the changes. This is a cause of concern for many people - 86% of respondents to the consultation held last year, opposed the plans.
Tom McClelland and Barry Flood, CTC representatives in Northern Ireland, joined protesters campaigning against the move.