Translink has been criticised by a Stormont watchdog for a lack of transparency over the level of reserves it holds.
The Regional Development committee said it had examined the public transport provider's accounts and found a series of unanswered questions.
Its chair Jimmy Spratt said members were also concerned about the "cosy relationship" between Translink and the Department of Regional Development.
Mr Spratt said the committee was recently "stonewalled" when they inquired about the firm's public accounts.
"The committee has examined Translink's accounts for 2012 and can see that it had total reserves of £19m," he said.
"However, the accounts also indicate that it has 'other reserves' of £50m but does not state to where or what these refer.
"In addition, they had £10.55m in cash held at the end of 2012 and £13.5m in short-term deposits.
"They were also able to clear a bank overdraft of £31m which was held at the end of 2011."
Mr Spratt also referred to the potential deficit relating to pension schemes, for which he said no explanation has been given.
"This is an organisation that has just raised bus and train fares by up to 8%; an organisation that has asked the department to bid for another £12m for new buses; an organisation that has £19m in reserves and £24m in cash and an organisation that is going to be guaranteed a lucrative contract for the next 10 years," he said.
The DRD officials who appeared before the committee yesterday to discuss the proposed new contract for Translink were Ms Anne Breen, project manager Public Transport Reform, Sean Johnston, programme manager Public Transport Reform, and David Strain, deputy principal Public Transport Reform.
Mr Spratt told the Belfast Telegraph the committee was becoming "more and more concerned" about the relationship between Translink and the department.
"It is our understanding that the Audit Office is in the process of conducting a major investigation into Translink," he added.
In April the Belfast Telegraph revealed that taxpayers ploughed almost £130m into Translink in the last financial year. Despite the £126.9m investment from the public purse, consumers saw fares on buses, trains and coaches increase by up to 8% on some services.