WASHINGTON (AFP) - US President Joe Biden lashed out on Thursday (Sept 2) at the Supreme Court's refusal to block a Texas law banning abortions after six weeks of pregnancy, warning that it threatens to unleash "unconstitutional chaos".

"The Supreme Court's ruling overnight is an unprecedented assault on a woman's constitutional rights under Roe v. Wade, which has been the law of the land for almost fifty years," Biden said in a statement.

Roe v. Wade is the landmark 1973 Supreme Court case that enshrined a woman's right to an abortion in the United States.

"This (Texas) law is so extreme it does not even allow for exceptions in the case of rape or incest," Biden said.

The Democratic president took particular aim at a provision of the bill passed by Republican lawmakers in Texas that allows members of the public to sue doctors who perform abortions or anyone facilitating the procedure.

"By allowing a law to go into effect that empowers private citizens in Texas to sue health care providers, family members supporting a woman exercising her right to choose after six weeks, or even a friend who drives her to a hospital or clinic, it unleashes unconstitutional chaos and empowers self-anointed enforcers to have devastating impacts," Biden said.

"Complete strangers will now be empowered to inject themselves in the most private and personal health decisions faced by women," he said.

Biden said he was launching a "whole-of-government effort" to "see what steps the federal government can take to ensure that women in Texas have access to safe and legal abortions."