A US federal judge has ruled in favour of temporarily halting a new law passed by Texas that severely restricts access to abortions in the state, in the first blow to legislation considered extreme even by conservative standards.

The decision is an initial victory for the Biden administration, which has challenged the restrictive law amid fears that other states might introduce similar measures. It also fears an escalation of the campaign to undo Roe vs Wade, the 1973 Supreme Court decision that legalised abortion nationwide.

US district judge Robert Pitman on Wednesday ordered Texas to suspend the enforcement of the law, which outlaws abortion after roughly six weeks of pregnancy, before many women know they are pregnant, without exceptions for rape or incest.