The 25-year-old had already been the subject of a transfer bid this summer, believed to be from Premier League outfit Sunderland.
It has not been made public whether the Black Cats are behind the latest offer. Nevertheless, chief executive Jez Moxey has insisted that the fee has again fallen short of the club's valuation of the striker.
"All parties need to draw a line under this matter, which has now dragged on for over a month," Moxey told the club's official website.
"We need to focus on the season ahead and these disruptions to the squad's preparations are unhelpful.
"We have always said we want to keep our best players. If our valuations of them are not met then they will remain at Wolves but we cannot allow this speculation about their futures to drag on indefinitely up to the closure of the transfer window."
Fletcher handed in a transfer request at Molineux last week.