Lord mayor Robert Doyle is being offered a campaign donation of hundreds of thousands of dollars by one of his fellow councillors in return for the deputy lord mayor nomination at Town Hall elections.

Ken Ong, the council's chair of planning, recently increased his sizeable wealth by selling a major stake in a chain of childcare centres he owns with his wife for at least $9 million.

Lord mayor Robert Doyle controls five of the 11 positions at Town Hall.

Cr Ong, a Liberal Party member like Cr Doyle, has told the lord mayor he wants to run as his deputy at elections in October.

In return for the position, Cr Ong said he was willing to offer a large campaign donation - with party members and Town Hall sources saying about $200,000 had been discussed.