The government must not spend money subsidising its plans for new nuclear power stations "on any account", the Conservatives have said.
Mr Duncan said Labour policy was "largely the same" as the Tories
Shadow business secretary Alan Duncan said his party's approach to energy was "largely the same" as Labour's.
He added that businesses should be "free" to invest in future projects but there should be no government money.
Mr Duncan also told MPs there also had to be "clarity on waste and decommissioning" of nuclear materials.
Business Secretary John Hutton earlier promised a new generation of "safe and affordable" plants, with the first completed "well before" 2020.
The government argues this will make the UK more independent of other countries in supplying its energy and reduce carbon emissions.
But environmental groups say nuclear power is expensive, dangerous and that there should instead be more focus on energy efficiency by homes and businesses.
Speaking in a House of Commons debate, Mr Duncan said: "Our vision on nuclear is clear.
"We must refine the planning system; we must have a price for carbon to establish a long term climate for investment; we must ensure there is clarity on waste and decommissioning; but on no account should there be any kind of subsidy for nuclear power.
"And from what the secretary of state has just said, our position is by and large similar to the government's.
"If business wants to invest in new nuclear power stations on that basis then they should be free to do so and they should know that the investment climate will remain stable under any Conservative government."