A group fighting to protect the rights of people with unwanted pregnancies will petition the Constitutional Court against Section 301 of the Criminal Code, which criminalises abortion.
The group wants the court to decide whether Section 301 goes against the rights and freedoms of women set out in the constitution.
Kritaya Archavanitkul, coordinator of the network that supports giving women with unwanted pregnancies more options, said Section 301 is a serious problem when it comes to terminating an unwanted pregnancy.
Those who aren't ready to have a baby and opt for an abortion can be charged with a crime when they are actually victims who need help, she said.
Also even though the law allows legal abortions for certain reasons, many of those who are eligible to have their pregnancy terminated lawfully are rejected by medical institutions, which claim they do not provide such a service, she said.
Legal abortions are allowed for three main reasons, namely a pregnancy that poses a physical or mental health threat to the mother, girls younger than 15 years old who have been raped and for foetuses with fatal abnormalities, she said.
The Referral System for Safe Abortions (R-SA), a network of non-profit organisations campaigning for better access to safe abortions, has also been working to help protect the rights of pregnant women who are allowed by law to seek and have an abortion, she said.
It has been working to make legal abortions available at as many hospitals as it can, she said.
Somwong Uraiwatthana, who handles calls to the Public Health Ministry's hotline No 1663 that offers advice to people with Aids or unwanted pregnancies, said 83% of more than 52,000 callers seeking advice between Oct 1, 2015 and June 30 this year, were regarding unwanted pregnancies.
About 7.6% of the 8,577 pregnant women who called the hotline between last October and June this year admitted having attempted to terminate their pregnancy themselves.
Of this number, 36 qualified for a legal abortion but were refused by various institutions, which claimed they were unable to help or would not do so, Mr Somwong said.
Somchai Peerapakorn, from R-SA, said if Thailand keeps denying access to legal and safe abortions, more women will turn to backstreet abortionists.
"Hospitals should have in place options for pregnant women as they do for patients with diabetes in terms of treatment," he said.