Rovers have struggled to replace the prolific Rickie Lambert, who joined Southampton in August, while Darryl Duffy was allowed out on loan to League One rivals Carlisle.
Fans' frustrations were only heightened after Tuesday's dismal performance in the 5-0 defeat at Leyton Orient, but Higgs insist there is money to spend.
"Money has been available throughout the whole of this season to strengthen the squad," Higgs told the Evening Post.
"We are running with the highest wage bill we have ever had, so we cannot be criticised for a lack of ambition.
"There has not been a great deal spent on transfer fees, but we have increased the wage bill significantly. We have secured some of our better young players, but money has been available.
"We have been unfortunate that we haven't found the players Paul Trollope and Lennie Lawrence feel could do the job for us. If it is deemed to be a good investment, we will consider everything seriously."
Source: PA
Source: PA