The House of Representatives Committee on Treaties, Protocols and Agreements and the Federal Ministry of Transport on Monday disagreed over commercial contract figures signed by the ministry.
The Chairman of the committee, Nicholas Ossai (PDP-Delta), at a public hearing in Abuja, said the ministry had signed commercial contracts worth $33 billion without clear cut ﬁnancing arrangements.
Mr Ossai said the essence of the probe is to get clarifications on all the agreements.
He said that there were more than 500 loans and bilateral agreements between Nigeria and other governments and international organisations.
"We have noticed from documents available to us that commercial contracts prices signed by the Federal Ministry of Transport alone within this period is over $33 billion without any clear cut ﬁnancing arrangements.
"Most of these commercial contracts agreements didn't also have local content clauses and there were no witnesses and designated and authorised officials.
"There are observable issues relating to procurement process evidence of 15 per cent advanced payments, payment of management fees, draw down process and remittances and a whole lot of other matters.
"We are strongly poised to ask questions and hope to get honest answers that will ﬁne-tune the current process, plan for possible renegotiation of some of these agreements in order to serve Nigerians better," he said.
The lawmaker said the parliament "cannot continue to approve loans without asking relevant questions."
Mr Ossai called on all key actors and stakeholders to stop the politicisation of the investigation.
"For us, if you believe in the progress and sustainable development of our country, then you should naturally cooperate with the work of this committee to see to it that there is guarantee of value for money in all government expenditures and borrowing plans, as well as government policies, programmes and projects," he added.
Responding, the Minister of Transport, Rotimi Amaechi, told the committee that there was no such loan of $33 billion in the ministry.
Mr Amaechi said the ministry had only signed a loan agreement of $1.6 billion under President Muhammadu Buhari's administration.
The minister explained that the amount was being used in the construction of the Lagos-Ibadan rail project.
He said that there were more than 20,000 Nigerians working on the project as well as 560 Chinese workers.
The minister said the Chinese government provided $1.2 billion while the federal government provided the remaining $400 million.
Mr Amaechi said another loan of $800 million was taken under the Goodluck Jonathan administration and that the project was 80 per cent completed before he was appointed minister.