Local Government NSW President Keith Rhoades has lambasted NSW Premier Mike Baird for sacking 378 local councillors without so much as a backward glance.

“He didn’t even have the respect or the manners to say: ‘I know this is a difficult time for those councillors involved and as Premier I wish to thank you for your services to the community of NSW and I wish you all the best’. In some cases it’s in excess of 40 years service,” Mr Rhoades said, unable to contain his anger.

Mr Baird announced the wholesale sacking of councillors on Thursday last week as he created 19 new councils, slashing the number of the state’s councils from 152 to 115. Twelve other merger proposals involving 31 councils are still in limbo, most of them held up pending court decisions.

Woollahra Council is expected to find out the outcome of its legal case any day now and Ku-ring-gai Council is in the Supreme Court on May 18.

It is likely that those mergers currently on the backburner will not be announced until after the July 2 federal election.

Administrators and interim GMs will run local councils until the September 2017 local government elections, as councillors exit stage left.

The new council teams are allowed to decide development applications but they cannot make changes to local environment plans or increase rates until councillors and mayors are appointed at the elections.

Opposition Leader Luke Foley said the decision to sack 42 councils demonstrated “considerable arrogance.”

“Democratically elected mayors and councillors have been dismissed and boundaries re-drawn,” Mr Foley said. “The new councils will be run by administrators, handpicked by the Premier. These administrators do not represent the community – they answer only to the Premier.”

State Labor has pledged to give councils the option to de-amalgamate, should it win the 2019 NSW election. The party has also called for a ban on developers sitting on councils and a cap on political donations.

Professor Graham Sansom, who led the Independent Local Government Review Panel that delivered the 2013 report on local government reform, has criticised the government for not keeping councillors on to help manage the complex transitions, as happened during the 2008 Queensland local government reforms.

Professor Sansom told the Sydney Morning Herald: “What you’re doing is disenfranchising a very large number of people simply because the government chose to amalgamate their councils, not because anybody has done anything wrong, and that’s why the Queensland approach is much better.”

Instead, councillors and mayors have been invited to serve on advisory groups, at least two representatives from each merged council, and still get paid. Councillors had to complete expressions of interest forms in April, including a 500-word statement about why they should be allowed to stay on, which caused widespread irritation.

But Mr Rhoades said advisory groups were unlikely to draw much enthusiasm from newly ousted councillors, despite Mr Baird’s insistence that the knowledge, skills and experience of existing mayors and councillors would be “an enormous asset to the new councils.”

Mr Rhoades said: “Why would you even waste your time working for them after the way you’ve been treated? That’s the feedback I’m getting from our members, they can just go and bite their butt. They’re just appalled and disgusted by the government.”

Advisory groups will contain at least two representatives from each former council area. There will also be local representation committees, which may contain former councillors and other local representatives.