He spoke amid a push by Prime Minister Benjamin Netanyahu to place the issue on the government's agenda when it meets on Tuesday afternoon.
Gantz's approval is necessary for such a move, but he has blocked the matter from moving forward.
"The government meeting will not entertain any reckless proposals at so sensitive a juncture," Gantz said.
It's presumed that such a wide policy declaration, which would expand the footprint of West Bank settlements in Area C, would be much more difficult to make as of Wednesday, when US President-elect Joe Biden takes office.
Biden is opposed to any settlement activity, particularly a declaration that speaks of a policy to so expand the territory on which Israel would build settler homes.
As a result, Netanyahu is under pressure from settlers and the Right to bring the matter to a vote on Tuesday, while US President Donald Trump is still in office.
Community Affairs Minister Tzachi Hanegbi has already written out the text of a government decision, so all the material necessary is ready for a vote.
For the last three weeks, settlers have manned a protest encampment outside the Prime Minister's Office. Two weeks ago, a small number of activists also began a huge hunger strike. Many of them had to halt their strike, after Gilad Farm resident Itai Zar fainted from hunger, was taken to the hospital and diagnosed with COVID-19.
Samaria Regional Council Yossi Dagan, who already had COVID-19 and who began his hunger strike only last week, was one of the few who continued with it. But on Tuesday morning, he fainted at the protest tent and was taken to the hospital.