The organisation, which has published a short set of charity policy recommendations to coincide with the Labour Party conference this week, said that the commission's guidance directed trustees to focus more on the survival of a charity than on achieving its mission.
Trustees should be making charities as relevant and vital as possible, rather than merely keeping them afloat, NPC said.
"NPC believes the language of the Charity Commission’s trustee obligations should be redrafted to focus less on acting in the interests of the charity, and more on the interests of the core mission of the charity," said a statement from Dan Corry, chief executive of NPC.
Corry said the trustees of a charity should be required to report to the Charity Commission every year on the impact of their organisation on its core mission, and its plans for improvement the following year.
"This would help to change the culture of the sector by bringing a focus on impact to the very top," he said.
The statement from NPC said political parties should encourage a culture that supported charities to achieve maximum impact in their activities so that the sector's resources were used most efficiently.
UK Community Foundations, the membership body for community foundations, has called on the next government to create special giving zones that would receive tax breaks.
Modelled on social exclusion zones, the giving zones would encourage investment in the areas of greatest need by providing tax incentives for donors.
Stephen Hammersley, chief executive of UKCF, said: "Our evidence is that philanthropists who have created their own wealth are interested in ways of using that wealth to achieve social good beyond traditional grants. They want to invest in their communities to promote sustainable development and to see their investment grow and achieve results beyond the initial sum. Treating donations as a social investment means money goes further and is used in a more sustainable way."
As part of its manifesto for next year's general election, released this week, UKCF recommends the continued use of match-funded endowment challenges to promote more local giving. It says that Community First, the existing 50 per cent match challenge programme, run through community foundations, created £45m worth of extra money for small charities and community groups last year, based on a £15m investment from the Cabinet Office.
Other UKCF recommendations include setting up a one-off £30m "philanthropy infrastructure investment fund", investing in smaller organisations to help them scale up their volunteering programmes, and working with the Charity Commission to take steps to discourage the establishment of new private trusts.