SYDNEY, Jan 20 (Reuters) - BHP Group investors in London and Sydney have approved plans to scrap the mining company's dual listing in favour of a main listing in Sydney.

More than 97% of investors voted in favour of the plan at a company shareholder meeting in London after the proposal won the support of more than 96% of proxy votes at an earlier meeting in Australia.

The decision will see the FTSE 100 index lose one of its biggest companies though it will retain a standard listing in London.

Owners of BHP's London-listed shares on the FTSE 100 account for 42% of the overall register split between London and Sydney.

Jefferies said "M&A deals could be coming" following the unification and once BHP completes the sale of its petroleum assets to Woodside Petroleum in the second quarter of 2022.

"An exit from oil & gas and a desire to increase exposure to 'future-facing commodities', which management has explicitly defined as copper, nickel and potash, could mean that BHP pursues acquisitions," they wrote in a note.

"CEO Mike Henry has recently talked about disciplined M&A being a lever for growth," they added.

The results of the votes will be published on the two stock exchanges later in the day. BHP shares were up 1% in London by 1615 GMT. (Reporting by Tom Westbrook in Sydney, Clara Denina in London, and Danilo Masoni in Milan Additional reporting by Zandi Shabalala Editing by David Goodman and Emelia Sithole-Matarise)