The campaign, launched last week, is intended to raise awareness of fundraising problems faced by disability charities by highlighting the fact that more people give to animal charities.
The Advertising Standards Authority is expected to launch an investigation this week after receiving 16 complaints about the posters, which are being displayed on buses and trains in Scotland.
An ASA spokeswoman said some complainants found the posters offensive, while others questioned the accuracy of a claim that 11.1 per cent of people donate to animal charities, whereas 6.6 per cent donate to disability charities.
Animal charities have also criticised the campaign, with some claiming that the comparison was unfair because Enable Scotland received government funding whereas animal groups did not.
Doreen Walkinshaw, head of fundraising and marketing at Enable Scotland, said: "We felt the discrepancy is something the public should be aware of. We are a service provider, but in Scotland only one in four disabled people receives a statutory service, leaving 9,000 with no service at all."
Doreen Graham, a spokeswoman for animal charity the SSPCA, said she hoped the debate would prompt the Government to reconsider which charities it funds.
"Animal charities don't receive government funding and can't apply for lottery money, so we are entirely dependent on public donations ," she said.