In an interview with the BBC, Alfonso Dastis said the move was in recognition of recent developments in Catalonia.
The Catalan government was deposed after a banned referendum and unilateral declaration of independence.
Protests were held against the detention of the region's ex-leaders.
Spain's constitutional court has ruled that the declaration of independence was "unconstitutional and void".
"We have created a committee in parliament to explore the possibility of amending the constitution to be able to accommodate better the aspirations of some of the Catalan people," Mr Dastis told the BBC.
"We acknowledge there is a political situation that deserves to be looked at but, in any case, it's clear that the decision will be taken, will have to be taken by all Spaniards."
He also said he was sorry if people got hurt during the banned referendum last month, but that there was no disproportionate use of force.
IS THIS AN OLIVE BRANCH TO SEPARATISTS?
Gavin Lee, BBC News, Barcelona reports that this appears to be an olive branch to supporters of separatism in Catalonia, who are protesting once again across the region. It offers the prospect of a referendum to change the Spanish constitution and therefore make it legally possible to hold a referendum on Catalan independence.
But what that means in effect, is that the entire population of Spain - 47 million people - would vote on whether Catalonia should have the right to self-determination.
Alfonso Dastis said the legal change might help resolve the Catalan crisis for future generations.
But it is a far cry from what deposed Catalan leader Carles Puigdemont had called for, the right for Catalans only to decide - BBC