Mike Sellers, director of Portsmouth International Port, claimed a successful bid for government cash could pave the way for more business.
Under government guidelines the ferry terminal will need to create new border checkpoints, which would require acquiring land ‘adjacent to the port' next year. Live animal compounds would also have to be constructed.
It is thought these updates could potentially take trade from other ports while money could be generated through the need for more customs agents from council-owned company Portico.
Speaking at a Portsmouth City Council cabinet meeting Mr Sellers said: 'Regardless of whatever type of trade deal we get this border operating model is required.
'But there are opportunities if we get the funding. There's a big opportunity if we get this right and have the facilities in place we can increase our income.'
It is thought the necessary changes will cost around £20m for which a bid has been submitted via the port infrastructure fund which totals £200m nationally.
At the meeting Councillor Hugh Mason said: 'If we do not receive the upwards of £20m we are expecting what is Plan B? What will we be unable to do - how will we manage?'
Mr Sellers explained there was no alternative plan. He said: 'I do expect the government will recognise we are compliant in regards the port infrastructure fund. Whether we will get the full amount is another matter.
'I expect we will get some of that funding especially around the border control point because legally we have to have those.
'There is a caveat within the fund. The £200m is in a pot and if it doesn't go far enough ports could be asked to contribute to that.'
Councillors confirmed any local authority investment would ‘obliterate’ council funds.
Deputy council leader, Cllr Steve Pitt, said: ‘If the council had to fund that £20m that would obliterate all the remaining resources and leave us in a position where it would effectively bankrupt the council. That's something we can't tolerate.’
Cllr Lee Hunt added: ‘That would equal a rise in council tax of about 40 per cent right now.’
As reported, among the additional work needed including modification to existing buildings and extension of freight gates for improved access to the M275.