Former Tory Cabinet minister Michael Portillo has led calls for the government to increase museum funding.
Museums partly rely on donations from the public
A cross-party group stated that UK museums made a "huge contribution" to the economy which was not matched by government investment.
Mr Portillo said there was an "enormous contrast" between money spent on museums and overall public spending levels under Labour.
Arts minister Estelle Morris pledged to do "her best" to secure more money.
MPs also criticised Treasury plans to withdraw the right of museums to claim tax concessions on donations.
Former Culture Secretary Chris Smith said withdrawal of gift aid tax relief would be "a severe financial blow to small museums up and down the country".
Mrs Morris said she realised the importance of the proposals.
"I am campaigning about gift aid. It's not the only comradely difference of opinion I have with the Treasury at the moment," she said.
"Museums are not just important to our past but to our present and our future. I just hope that the power of the argument we make is heard in the corridors of the Treasury," she said.