Itchen MP John Denham, said he would meet with Associated British Ports (ABP) over the "unfair competition".
The government is taking a new look at the Liverpool's application, which had previously been rejected.
Transport Minister Mike Penning previously said he wanted to "maintain a level playing field across the UK cruise industry".
Labour MP Mr Denham is due to meet ABP director Doug Morrison on Monday.
Currently cruises can call at Liverpool but not start or end journeys there.
ABP, which runs Southampton's port, said it believed EU subsidies paid to the Liverpool terminal amount to "unfair help".
Liverpool City Council said between 25 and 40 liners could be expected in the city each year if the plan went through.
This was about 4 to 6% of the market, which was worth between £6.6m and £10.6m, a spokesman said.
The government needs to approve the plan because a £9m EU grant helped pay for Liverpool's £20m cruise liner terminal, whereas Southampton is commercially-funded
