Google has reversed a decision that stopped Australia's largest abortion services provider placing advertisements on its platform.

It followed calls from Greens Senator Larissa Waters for the company to explain the move while pushing for representatives to give evidence at a parliamentary inquiry into universal reproductive healthcare in Australia.

The tech giant stopped online ads being published by MSI Australia, a decision the provider estimated would impact between 700 and 1500 people per week.

But a Google spokesperson confirmed the company had reviewed the ads and they were back online.

"We have longstanding policies that govern abortion-related ads on Google's platforms. Abortion-inducing drugs are not allowed to be advertised in Australia," the spokesperson said.

"After reviewing the ads in question, we communicated with the advertiser and their ads are now compliant and showing again."

A spokeswoman for MSI Australia told AAP while the ads had been published, they were limited under Google's birth control policy and the company was following up on why this was happening.

She said Google originally wanted the provider to remove the term "medication" from its website, but MSI Australia pushed back on this.

"We need health information explaining the medical and surgical abortion processes on our website," the spokeswoman said.

"The interim solution we agreed on with Google was to remove the word medication from our ad landing page (which is now our homepage) and then they reinstated the ads."

The spokeswoman said advertising restrictions to services surrounding abortion care were unacceptable because they limited access to critical healthcare.

Earlier, Senator Waters wrote to the online search giant 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, being promoted in Australia, medical services such as abortion clinics are allowed to promote themselves.

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.

The cost and accessibility of contraceptives, abortions and healthcare information across the nation will be examined by the Senate 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.