FILE PHOTO: Migrants walk along a street after passing the Austrian-German border near Wegscheid, Germany, November 12, 2015. REUTERS/Michaela Rehle/File Photo

BERLIN (Reuters) - Germany’s top court on Tuesday rejected a complaint from the far-right Alternative for Germany (AfD) against Chancellor Merkel’s government over its liberal asylum policy.

The constitutional court said the AfD - the biggest opposition party in Germany’s lower house of parliament - had failed to demonstrate how Merkel’s decision to open the borders to migrants in 2015, without asking the German parliament for approval, could have affected the party’s constitutional rights.

The court refused to even hear a lawsuit that the AfD’s parliamentary group had brought in May.

The decision marks a blow for the anti-immigration party, which has heavily campaigned against Merkel’s migration policy - an issue which helped it win seats in the national parliament for the first time in the September 2017 election.

The AfD said Germany should have sent back asylum seekers, many of whom came from Syria via the Balkans, as they made their way into Germany in 2015 and the government should have sought parliamentary approval to open the borders.

The party asked the court to state that an approval by Germany’s Bundestag would have been necessary to justify Merkel’s - in its view - far-reaching decision. The court rejected this argument, saying that the AfD only gained representation in parliament two years later.

The court said a constitutional claim brought by a parliamentary group against the government could not be used to determine whether or not a government decision was constitutional, unless it affected the party in its own right.