THE German government asked the US what information its National Security Agency (NSA) had collected on Angela Merkel after monitoring her mobile phone for years but got no response, a German lawmaker has said.

Omid Nouripour, a member of parliament for the opposition Greens, asked the German government in a formal parliamentary query if it had contacted Washington to discover what the NSA found out.

"I wanted to find out what the German government was doing about the NSA eavesdropping on her," Nouripour said.

In a reply dated April 7, an official in the interior ministry who was tasked with answering Nouripour's questions replied that the government had asked about any information on Merkel but received no answer.

"They didn't ask firmly enough," Nouripour said. "If you ask half-heartedly, you won't get answers. Merkel needs to keep pressing for answers."