Health Minister Mark Drakeford said he fears that electronic cigarettes are "re-normalising" smoking and believes there is a case for tighter laws.
He told BBC Wales' Sunday Politics that he was very anxious about the devices.
But he did not dismiss claims that e-cigarettes may help people quit smoking.
Legislation is going through parliament to ban their sale to under-18s in England and a vote in the assembly on Tuesday would extend it to Wales.
E-cigarettes have recently be found to be just as effective as nicotine patches in helping smokers quit.
Rather than inhaling the toxic substances found in tobacco, e-cigarette users inhale vaporised liquid nicotine.
"I am far more worried that the e-cigarette movement is re-normalising smoking, that it's re-glamorising smoking," Mr Drakeford said.
"It contains nicotine and nicotine is highly addictive. And what we don't want are e-cigarettes to become a gateway to real cigarettes."
Smoking in enclosed public places has been illegal in Wales since 2007.
Asked if restrictions on smoking tobacco should also apply to e-cigarettes, Mr Drakeford said: "I think there's a very powerful case for being exactly that.
"If you lived in New Zealand for example you can only buy an e-cigarette at a pharmacy because they regard them entirely as to be governed as a health issue and as a medicine.
"There are things we can do in Wales and we want to explore with the public."
He added that this was "a new area" and the "evidence was unclear".
"This is a rapidly moving picture and we need a debate with the wider public about exactly what we ought to do," the minister added.
Further proposals are expected be included in a forthcoming Welsh government white paper on public health.
Meanwhile, the Welsh government is running a publicity campaign to encourage smokers not to light up in cars carrying children.
Based on feedback from the campaign, ministers will look at changing the law to ban smoking in cars when children are on board.
The House of Lords last week backed a Labour amendment to the Children and Families Bill designed to introduce a ban in England.
Mr Drakeford said: "I think we will wait to see what the evidence tells us. I'm not going to pre-empt what that evidence may say.
"If legislation is needed then we will legislate in Wales."