"We must not buy average players," Eriksson told Manchester Evening News.

"We have to buy top-class and for them to be better than we have already. That will cost a lot of money."

City have enjoyed a tremendous start to the Premiership under the Swedish tactician, their best in 50 years, lying third in the league table.

Thaksin Shinawatra, City's Thai owner, invested heavily in the summer but Eriksson hasn't had enough.

"I am told there is money available in January but how much I don't know yet," the former England manager said.

"Before I get into lists of players in whom we might be interested I think it is vital to know what that spending figure will be."