Former deputy leader of the Nationals Adrian Piccoli has sparked an uproar in State Parliament by miming shooting Labor MPs to make a point about their preference deal with the Shooters, Fishers and Farmers Party in the Orange by-election.

The Nationals had held the seat of Orange by a margin of more than 21 per cent, but they suffered a significant swing against them in the weekend’s by-election, in favour of Shooters candidate Phil Donato.

The preference deal between the Labor Party and the Shooters has helped produce a result which might see the National Party lose the seat for the first time since 1947.

Mr Piccoli used Question Time to slam Labor for preferencing Mr Donato, saying the Opposition was supporting a party that wanted to get rid of John Howard’s national gun laws.

Mr Piccoli then started talking about the massacre at Port Arthur, pointing his finger at the Opposition benches while shouting “bang, bang”.

“Bang! Bang!”

Mr Piccoli said Opposition leader Luke Foley had been “celebrating” the result in Orange with the Shooters party.

“So what’s he celebrating?” he asked.

“AR-15 assault rifles? Because that’s what they want in NSW. That’s what you’ve given them.”

The Opposition benches erupted with calls of “you’re a disgrace”.

Shooters fall behind Nationals at the 11th hour

Counting will resume tomorrow to decide the result of the Orange by-election.

The Nationals’ candidate Scott Barrett now leads Mr Donato from the Shooters Party by about 65 votes.

Discrepancies in the number of votes prompted a re-count of preferences which will begin tomorrow morning.

The Shooters Party issued a statement saying they believed there was “an error in today’s count by a factor of 100 votes”.

“According to our figures, there may be an error in the calculation of preferences from another candidate,” the statement read.