Toyota has returned to the top slot in global vehicle sales after releasing figures for the first nine months of the year.

The Japanese carmaker sold 7.5 million in the first three quarters of 2015, beating Volkswagen's 7.43 million and General Motors' 7.2 million.

After six months of the year, VW was ahead of Toyota, in pole position for the first time.

VW's emissions scandal emerged towards the end of September.

The discovery of software that was able to mislead emissions tests on diesel cars may have more effect on VW's sales in the remainder of the year.

Toyota's sales for the first nine months were 1.5% below the level at the same stage last year.

Toyota first overtook GM to take the top slot in 2008 and has kept it every year since, except 2011 when GM was the top seller after a tsunami in north-eastern Japan disrupted Toyota's production.

New GM labour contract

Separately, there was relief for General Motors on Sunday when it reached an agreement with the United Auto Workers union, averting a threatened strike.

Details of the four-year labour deal were not released. It will now go to a vote of UAW leaders and then the union's 52,700 workers at GM.

"We believe that this agreement will present stable long-term significant wage gains and job security commitments to UAW members now and in the future," said UAW president Dennis Williams.

The union had threatened that it would terminate its existing contract at midnight Eastern time on Sunday, meaning there could have been a strike.