MP Ian Lucas has urged Wrexham council to be as "open as possible" after spending £486,691 on consultants and legal fees in a year.
The Wrexham Labour MP said the council initially would not reveal the figures, which were eventually released when he made a Freedom of Information request.
The Liberal Democrat-led council said it was "open and transparent".
But it said the figures were originally not released because they included "personal business information".
Mr Lucas said he obtained the figures after they were circulated in a report to councillors, but were not made available to the public.
He said fees paid to consultants and lawyers for the period from 1 April, 2009 to 31 March, 2010, was more than £486,691.
He said: "The council originally gave these figures to councillors in a report, but that report was restricted which meant the figures were not to be released.
"Indeed, the council did not release the figures to me on my first request.
"I then put in a Freedom of Information (FoI) request and eventually obtained the relevant report.
"The council cited commercial confidentiality as part of the reasoning behind its actions.
"With the current climate on spending and costs, I believe it is important for the council to be as open as possible about what public money it is spending, where that money is being spent and why.
"I understand the council's concerns over commercial confidentiality.
"However, that should never be used an excuse for the council to not reveal what it is doing with a significant chunk of taxpayer's cash.
"As Parliament has already discovered, trust is undermined when there is a lack of clarity over how the public's money is spent."
Aled Roberts, leader of the council said in a statement: "Wrexham council prides itself on being an open and transparent organisation and we have provided the information to Mr Lucas as requested under the FOI enquiry.
"The information was exempt for release because it included personal business information.
"The amount of money being spent by the council has been reducing steadily in recent years and members are provided with regular reports with regards about spend in this area.
"Compared with others he can be assured that extra costs and fees are only incurred where absolutely necessary."