Pam Baker, the women's lawyer, said that a Hong Kong judge, approached with an application for leave to seek a judicial review, had postponed their deportation until Thursday morning.
'It's a triumph. We're thrilled to bits, but it's only one step,' said Ms Baker, who is on a private visit to Britain.
On Thursday there will be a hearing before the Hong Kong Attorney General, the colony's most senior government lawyer.
Amnesty International has said both women would be at 'serious risk' of being jailed if sent back to China.
They fled China earlier this year to avoid being arrested for their involvement in the pro-democracy movement.
Chen Yu wrote articles critical of the authorities during and after the Tiananmen Square protests. Her poems were distributed among many of the protesting students who were later killed.
Lin Lin was forced to write confessions and undertake not to have any involvement with dissidents after travelling to Beijing during the protests. She later gave Chen Yu shelter.
The women paid a smuggler to take them into Hong Kong, where they applied for political asylum while held in detention.
The Home Office said asylum had not been granted because Hong Kong did not believe either woman was at serious risk.