The matter is set to be debated for the 21st time tonight.

An extraordinary meeting held last week was adjourned so the council could seek legal advice about three proposed motions.

The first, moved by Cr Bob Cook and rejected seven votes to six last week, was to undertake an expert assessment before a NSW Land and Environment Court injunction was due to expire.

Cr Michael Osborne had proposed asking the state government to intervene in the matter.

Labor councillors backed a motion to close Laman Street to traffic, erect warning signs, review the council's tree policy and to ask Premier Barry O'Farrell to arrange an expert assessment of the trees.

Senior Counsel John Griffiths said he considered all three unlawful.

"When viewed as a matter of substance and not form, each of these motions puports in different ways to rescind or at least alter the terms of the 19 July resolution [to remove and replace the trees as soon as practical]," Mr Griffiths wrote.

"My opinion is not altered by the fact that an undertaking is currently in place in the NSW Land and Environment Court not to remove the trees."

Mr Griffiths also dismissed legal advice, quoted by lord mayor John Tate at last week's meeting, from Save Our Figs barrister Mark Robinson SC.

He said Mr Robinson "does not adequately address the terms" of a section of the local government act that says a three-month moratorium on rescission motions "cannot be evaded by substituting a motion differently worded, but in principle the same".

If Save Our Figs wins an injunction beyond November 25, the council would then be able to lawfully vote to rescind its decision to remove the trees.