Mayor Boris Johnson has ruled out introducing a Travelcard for part-time workers.
Liberal Democrat and Conservative members on the London Assembly want the Mayor and Transport for London to make it cheaper for part-time workers to use public transport.
Appearing before Assembly Members on Wednesday, the Mayor claimed the revenues lost from introducing such a ticket would mean increased fares for other passengers.
He repeated recent calls for the Government to introduce a tax-break for season ticket holders.
However Caroline Pidgeon, Leader of the Assembly’s Liberal Democrat group, suggested few part-time workers earned enough to benefit from such a policy.
Conservative AM Andrew Boff criticised the Mayor for “listening too much to your advisors at TfL” and ignoring cross-party calls to introduce the ticket.
Speaking after the meeting Ms Pidgeon described the Mayor’s stance as “deeply disappointing”.
She added: “The whole Travelcard system is centred around the old fashioned idea of everyone working a five day week in an office environment. That simply isn’t the real working experience anymore for many people.”
“The Mayor, as chair of Transport for London, should stop making excuses and instead ensure that people who work part-time or regularly work from home are given a fair deal.”