The number of councils in Sydney would be slashed by about half under a draft plan being canvassed within the state government.

A list of possible council mergers is being circulated to nervous Coalition MPs, Fairfax Media understands, as Local Government Minister Paul Toole attempts to gauge levels of community hostility or support for reform plans.

In one scenario under discussion, Parramatta would be merged with at least Holroyd. The City of Sydney, which was recommended for amalgamation in a 2013 report, would remain as a standalone council.

It is understood that the options being aired are preliminary only. But the fact that groupings are already being talked about – well before a separate process run by the Independent Pricing and Regulatory Tribunal (IPART) concludes – is an indication of the sensitivity of government MPs to any potential changes.

One change being considered would merge Waverley and Randwick councils with Woollahra, while another grouping proposes nearby Botany be amalgamated with Rockdale as part of a new south Sydney council.

A merger between some of Sydney's inner west councils features on the list, as does an amalgamation of Canterbury and Bankstown.

Across the harbour, merging Mosman, Willoughby and North Sydney is being looked at, as is merging Lane Cove with Hunters Hill and Ryde.

The list comes well ahead of IPART's findings about whether councils are either "fit" or "unfit" as merged groups or individual councils.

IPART, which is now assessing proposals from each of the state's councils – most of which are opposed to mergers – is not due to deliver its recommendations to Mr Toole until October.

Under the draft groupings circulated, Sydney's 41 councils would be cut to about 22. This is a higher number than was set out in 2013 by the Independent Local Government Review Panel, which said having between 15 and 18 councils was "appropriate".

The Premier's office and Mr Toole's department have also begun investigating measures that would allow them to more easily implement amalgamations once the government receives IPART's report.

A document prepared for the cabinet sets out six legislative options that would smooth the way for forced mergers, including sacking all of the state's councils and appointing administrators.

But this option, aired at the weekend and rejected by Mr Toole on Monday, is not recommended. Nor is keeping the existing system, which requires the government to apply to the independent Boundaries Commission or the head of the Office of Local Government if it wants to merge councils.

Instead, amalgamations negotiated through Parliament is set out as the safest option and the one least vulnerable to legal challenge.

But for this path the government would need the support of either the Shooters and Fishers Party or the Christian Democrats, who have joined Labor and the Greens in vowing to block any forced mergers in the upper house.

Streamlining the Boundaries Commission was assessed, but it was noted that this option risked delaying the process. A governor proclamation, either with or without public notification, was also canvassed.

The Carr government used a proclamation in 2004 when it merged councils, including amalgamating the former South Sydney council into the City of Sydney.

Asked about the list and the options prepared for cabinet, a spokeswoman for Mr Toole said IPART would report back in October and "the government will then be in a position to decide the next step forward".

"The government is at present consulting with councils, stakeholder groups and the community about these important reforms," the spokeswoman said.