The comments came after Brussels on Tuesday said that checks introduced at the height of the 2015 migrant crisis by Austria and four other countries must end by November.
"If the European Commission is now saying that another extension of the national border controls beyond November is not possible because of legal reasons, then we need jointly to adapt the law to ensure that additional controls are necessary," Defence Minister Hans Peter Doskozil told the Austria Press Agency.
"If border controls are necessary because the number of illegal migrants rises again then we shouldn't hide behind bureaucratic rules but make border controls possible," Foreign Minister Sebastian Kurz added on Oe1 public radio.
Austria, Denmark, Germany, Sweden and non-EU Norway introduced the checks in 2015 and have extended them several times. But Brussels said a six-month extension from mid-May must be the final one.
Sweden said on Tuesday it was suspending systematic checks on its border with Denmark.
A migrant deal between the European Union and Turkey has dramatically slowed the influx, although tens of thousands of people have attempted the treacherous sea journey between Libya and Italy so far this year.
Doskozil said that 9,700 migrants have entered Austria this year, 6,600 of them applying for asylum.