Officers involved in the case are flying to Germany today, in an effort to question Hewlett, 64, who is recovering from throat surgery in hospital in Aachen.
A spokesman for Aachen police confirmed the public prosecutor will decide whether to give Hewlett the test in the next few days.
The convicted child rapist was living near the Algarve resort at the time when Madeleine disappeared while on holiday with her parents in May 2007.
Police will use the results of the test to determine whether they match samples taken from the McCann's holiday apartment, which so far have not been linked to anyone.
The family's spokesman Clarence Mitchell said he hoped Hewlett would comply with the tests.
'Mr Hewlett has denied any involvement in Madeleine's abduction,' he said.
'Our
investigators hope he will co-operate by
giving them whatever information is needed
so they can eliminate him from the
investigation.'
News of the DNA test comes as the wife of Hewlett declared him ' innocent' after it emerged that he was well acquainted with the resort where the McCanns were staying.
Marianna Schmuker said her husband had nothing to do with the little girl's disappearance, despite reports he was seen outside the apartment in Praia da Luz 'many times'.
His family live in an apartment in the city.
Yesterday a man who knew Hewlett came forward to reveal he had talked non-stop about the Madeleine case in the weeks after she vanished in May 2007.
Hewlett boasted of knowing Praia da Luz 'very well' and being familiar with the Ocean Club complex where Kate and Gerry McCann were staying with their children and friends.
