The local authority made £116,000 more than it thought it would in penalty charges in the last 10 months.
This money was used to offset the council's parking budget which was in the red to the tune of £297,000 because of non-payment and administration of parking fines.
But it still leaves it £163,000 behind budget for the year to date.
The figures, tabled at the council's finance committee, have raised concerns about the local authority's dependance on bus lane fines.
Former bus driver and SNP councillor Malcolm Balfour said: "What you are seeing is fines taken from people who mistakenly strayed in bus lanes - some when there wouldn't have been any buses on the road - propping up other failing budgets.
"The council has assured that the money collected from bus lanes is used on 'transport strategies' but drivers have been shown no evidence of this.
"The fact that they collected £116,000 more than expected in the time period is alarming in itself.
"As reported in the Evening Times, an independent motoring expert has already said that if the lanes are raking in thousands they are not working.
"A successful bus lane, one that is in the right place and adequately marked out, should not catch anyone out."
A report, presented to the council's finance committee, reads: "Parking has a net overspend of £163,000 largely due to an over-recovery of bus lane camera enforcement income (£116,000), offset by an under recovery of Penalty Charge Notice income during the period and some additional parking meter maintenance costs.
"The service will continue to closely monitor the bus lane camera enforcement income as experience elsewhere suggests this income stream will diminish as time progresses."
Glasgow City Council coined in £2.5million in penalty fines last year from 15 camera enforced bus lanes across the city.
The council decided not to charge people this coming Christmas and New Year's Day - when there were no buses on the road - after we revealed it issued 370 fines for the same period this year.
Mr Balfour said: "The council cannot and should not be banking on this cash."
The councillor has launched a petition calling for a review of bus lanes across the city and their operating hours.
Despite there being no 24-hour bus services in the city, there are 10, 24-hour bus lanes.
The petition is available to sign at http://www.ipetitions.com/petition/buslane