A German film about second world war general Erwin Rommel has been criticised by members of the soldier's family, who say it depicts him as a Nazi criminal who was in thrall to Hitler.

A famed military tactician, Rommel was known as the Desert Fox for his victories with the Afrika Korps over the British 8th Army in north Africa. Widely respected in Britain and Germany during and after the war, he was implicated in the July 1944 plot to kill Hitler and often refused orders to murder Jews and other minorities captured during battle. But the new film, produced for the German TV channel SWR, suggests Rommel's attitude to the Nazis was ambiguous at best and has prompted an angry reaction from the general's family. They say advance publicity for the film depicts Rommel as "an upstart, a favourite of Hitler and a Nazi war criminal".

"This is simply untrue. These are lies," the family wrote in a letter to SWR director general Peter Boudgoust. "Yes, he did value Hitler in the beginning, because he was a friend of the army, but the mutual admiration ended abruptly with Hitler's 'victory or death' order before El Alamein, which resulted in Rommel withdrawing his troops of his own accord and saving many lives."

Rommel is known to have become more critical of the Nazis as the war progressed. However, he was also a confidant of propaganda minister Joseph Goebbels, who ensured details of his exploits were made public and helped build his image as a German hero.

Hitler discovered the plot to assassinate him in the final years of the war. Concerned that execution of a German war hero would affect morale, he gave Rommel the choice of a show trial or suicide. The general was approached at his home by two fellow generals from Hitler's Berlin HQ in October 1944 and told that only the latter choice would ensure the safety of his family, along with a generous pension and a hero's state funeral. They brought with them a capsule of cyanide, which Rommel eventually took.

The film, by director Niki Stein, casts German actor Ulrich Tukur as Rommel. Its producers say they have taken all possible steps to ensure historical accuracy, though Stein has admitted that he sees the general as the hero of a generation of wartime Germans who "realise only gradually and too late that the person they have served with such passion is a criminal".

"[The film] shows the conflict Rommel had between his involvement in the Third Reich and his growing resistance to Hitler," said Nico Hofmann of production company ARD-Film. "The screenplay is based on months of research with the support of leading historians. We have gathered all the recent significant research findings on Rommel."