It was the first time in his parliamentary career that he sided with the Liberal-Nationals coalition.
He told AAP he was "no longer bound" by the Labor party and that as an independent he did not support gags in Parliament.
"I've always said that when I became an independent I would look at all issues on their merits, but support the Government on supply and confidence motions," Thomson said.
"I am looking out for what's best for the people of the [NSW] central coast."
Opposition frontbencher Joe Hockey told Parliament yesterday morning that the coalition was not prepared to accept Thomson's vote and that manager of opposition business Christopher Pyne would withdraw from the chamber.
There was confusion as Deputy Speaker Anna Burke said the chamber doors had closed and MPs could not leave.
Pyne said he had left the chamber to "negate the tainted vote of the member for Dobell".
The Hansard record shows no MP "pair" was given to Thomson and that his vote is listed alongside that of Opposition Leader Tony Abbott.
Abbott said the coalition would never give a "pair" to an independent.
"We will never accept Thomson's vote under any circumstances," he said.
The NSW ALP is expected to open nominations for the pre-selection in Thomson's seat of Dobell in September.
- AAP
