Abortion access is being examined as part of a Senate inquiry into universal reproductive healthcare in Australia.
The Greens are pushing for the search giant to give evidence at a committee hearing following its decision to stop online ads from being placed by MSI Australia, the nation's biggest abortion and reproductive health services provider.
Greens senator Larissa Waters wrote to Google requesting an explanation and said there was no justification for its refusal to advertise MSI Australia's services.
"Restricting information about medical abortion can prevent people from understanding this option within the timeframe in which the procedure is legally available," she said in the letter.
"This can result in people who decide to terminate requiring more invasive and expensive surgical abortions."
While medical advertising laws stop prescription medicines, including abortion-inducing pills, from being promoted in Australia, medical services such as abortion clinics are allowed to promote themselves.
MSI Australia managing director Jamal Hakim said Google's ban had misinterpreted Australian law and regulations.
"Abortion is legal in Australia but it is not easily accessible. Google's ban is restricting abortion access," he said in a statement.
Senator Waters said medical abortion was a lawful healthcare procedure but information about where and how to access it was not readily available.
"Without advertising to provide accurate, responsible information, many people in need of compassionate, expert advice about pregnancy options and termination care will not be able to find it," she said.
"I request that Google immediately review the recent decision to prevent MSI Australia from advertising its medical abortion services and revoke any blanket ban."
The cost and accessibility of contraceptives, abortions and healthcare information across the nation will be examined by the committee, as well as medical training options for doctors and allied health nurses.
It will also look at sexual and reproductive healthcare accessibility for transgender and non-binary people.