The Liberal Democrats report 51,000 armed forces personnel receive lower pay than a newly recruited police constable or fire fighter. The basic, lowest-paid private currently earns a salary of £16,681.
According to research from the Party, 60% of lower ranks in the marines are dissatisfied with pay compared with only 20% of other officers.
The Liberal Democrats are calling for a basic pay rise of £155 per week for fully-trained privates, £73 more a week for ranks up to lance corporal and £20-£30 per week more for other non-commissioned officers.
It estimates these pay rises would cost an extra 1% of the Ministry of Defence's bonus.
Liberal Democrat leader Nick Clegg said: "We can't reward lions with peanuts. Action must be taken now to restore the military covenant between the armed forces and the people.
"As a fundamental part of this we would put service personnel and their welfare at the heart of defence policy. We will ensure no soldier, sailor or airman goes into harm's way on less basic pay than a new recruit to the police or fire service."
But the Ministry of Defence (MoD) reports a private soldier deployed on operations will now receive basic pay between £16,681 and £25,887, a minimum of £1,194 in Longer Separation Allowance over a six-month tour; and £2,380 tax-free Operational Allowance over a six-month tour.
This brings the minimum pay for a private deployed on their first operation up to at least £20,255.
A MoD spokesperson said: "Armed forces pay is recommended by the independent Armed Forces Pay Review Body (AFPRB). In February, the AFPRB recommendations were accepted in full by the MoD to give all serving personnel a pay increase of 2.8%. This is the third year running that armed forces pay increases have been among the best in the public sector."
