Volkswagen was expected to announce on Monday it is expanding its US goodwill diesel emissions compensation programme to tens of thousands of owners of larger diesel vehicles, the company's top US official told Reuters.

Volkswagen Group of America President and CEO Michael Horn said late on Sunday on the sidelines of a media event that VW would announce on Monday at an event at the Detroit show the expansion of its programme that provides US$500 in cash and $500 in credits at dealerships to owners of its 2009-2016 diesel VW Touareg SUVs.

VW announced in November it was offering the compensation for 482,000 owners of 2009-2015 2.0 litre diesel cars. Horn told Reuters on Sunday more than 260,000 owners have signed up – or more than half – and 130,000 have already been paid.

But it didn't extend the compensation to larger vehicles involved in a related emissions issue.

In November, VW also admitted it failed to disclose emissions controls in about 80,000 3.0 litre SUVs – including the 2009-2016 VW Touareg, 2013-2016 Porsche Cayenne and 2014-2016 Audi A6 Quattro, Audi A7 Quattro, Audi A8, Audi A8L, Audi Q5 and 2009-2016 Audi Q7 – which allowed vehicles up to nine times legally allowable pollution levels.

An Audi spokesman on Sunday told Reuters a similar goodwill programme was on the way for its three litre vehicles.

Reuters said expanding the compensation could add as much as 80,000 vehicles and $80m to the compensation programme if Porsche and Audi expand it to all larger diesel vehicles.

Horn told Reuters on Sunday the portion of VW owners that have complained or sought buybacks is "minimal". He said VW polls at least 1,000 owners every two weeks to gauge how consumers are reacting to the emissions scandal.

Horn said he didn't expect US sales to rise in 2016 – after VW brand sales fell 5% in 2015.

He said things have changed at Wolfsburg-based Volkswagen – the world's second largest automaker. Horn said he has the mobile phone number of VW CEO Matthias Muller, something he never had with the former CEO Martin Winterkorn, and is getting quicker answers to questions.

Horn said it took VW's management team in Germany two weeks to approve the $1,000 US goodwill compensation programme – something that under the prior management would have taken six months.