Health Minister Michelle O'Byrne needs 13 votes to get the Reproductive Heath Bill through the lower house.

A Liberal Party staffer confirmed that none of its 10 members will vote for the legislation, despite being granted a conscience vote.

Speaker Michael Polley will vote against the legislation.

Attorney-General Brian Wightman and Denison Labor MHA Graeme Sturges have been tipped to vote against the legislation, as both voted against voluntary euthanasia, but neither has declared their vote.

Both Mr Wightman and Mr Sturges voted for marriage equality legislation last year.

Braddon Labor MHA Brenton Best previously expressed concern about the 24-week cap in the draft legislation, but has not stated his position on the revised legislation, which lowered the cap to 16 weeks.

Despite Liberal Party statements, supporters of the legislation remain optimistic that Liberal Party deputy leader Jeremy Rockliff and Braddon Liberal MHA Adam Brooks will vote for the legislation. Mr Rockliff has said he supports decriminalising abortion.

Liberal Party members have expressed concerns about some aspects of the legislation, such as the inclusion of socio-economic factors in the list of reasons a doctor may take into account in deciding to perform an abortion after 16 weeks.

A requirement that doctors with a conscientious objection to abortion direct the patient to other doctors who they reasonably believe do not share their objection is also a sticking point.

Greens leader Nick McKim will move an amendment that would mean anti-abortion groups could still protest outside abortion clinics, providing they did not interfere with, intimidate, harass or obstruct people going into the clinic.

Under the legislation as it stands, protesting about abortion or harassing, intimidating or assaulting people within 150 metres of the clinic would be met with a $65,000 fine or one year's imprisonment.

Mr McKim has said he will otherwise support the legislation.