METROPOLITAN police stations could be closed to help cut the police budget by $150 million.

Police Minister Michael O'Brien said the closure of smaller "shop-front" stations is among measures being discussed to meet the savings target over the next four years.

"There's been a significant decline in patronage at what I call the shop-front, outlier police stations," he said.

"It could well be that the smart thing to do is to wind back on a number of those and get those police officers out on the beat.

>> Where would you find the budget savings for SA Police? Check out the financials of the annual report and tell us in the comments box below.

"Increasingly the public of South Australia are embracing online solutions and SAPOL are increasingly moving to receiving a whole range of reports ... by online lodgement."

Mr O'Brien said country police stations were not being considered for closure "at this stage".

Mr O'Brien said he will explore possible cuts with Police Comissioner Gary Burns over the next three days, but reiterated a State Government commitment not to cut police numbers.

"We will find the maximum savings that we can within SAPOL but they will not be savings that will in any way bring about a reduction in the size of the police force," he said.

"I don't believe at this point in time, from what I have seen, that they will be sufficient to get us to where we want to be so we may have to return to the budget process and do a top up."

It comes as South Australia's police union today meets Commissioner Gary Burns amid grave concerns the number of officers on the beat must be cut to meet huge savings ordered during the next four years.

Mr Burns has been asked to find $150 million of savings from the SA Police budget over the next four years. He will meet police union representatives today after yesterday conceding savings likely would be made through reduced staff costs .

In 2011-12, SA Police spent $616.5 million on employee benefits expenses and $134.5 million on supplies and services.

Check SA Police's financials, starting on page 104 of their 2011-12 annual report, and leave your suggestions for how the budget savings target should be met in the comments box below.

Premier Jay Weatherill and Police Minister Michael O'Brien have ruled out any reduction in police numbers.

But Police Association president Mark Carroll told adelaidenow the union's members had grave concerns about the implications of cuts for frontline officers.

"With budget cuts of this magnitude now expected in the next four years, it will be extremely difficult to meet them without reducing staff numbers," he said.

"The Government has committed to recruiting an additional 313 police by 2016. Imposing massive cuts to the police budget seems at odds with that promise.

"The association is meeting with Commissioner Burns (today) and will formally request that he identify where the savings will be made."

The budget cuts are in addition to a forecast reduction in sworn officers and cadets - down by 71 to 4535 in June 2013 - compared with a year ago.

Victims' Rights Commissioner Michael O'Connell said any cuts to services would be detrimental to victims and the public in general.

"Victims and other members of the public want the police to be seen dealing with crime, enforcing the law and keeping them safe," he said.

"Hopefully, the cut in the police budget does not impede the Commissioner who is committed to making the police visible, responsive and available."

Mr Burns said almost 80 per cent of the police budget was tied to salaries, wages and superannuation.

"To find those savings will be a very difficult exercise for us," he said. "The last thing we want to do is reduce police numbers but it's on the cards that we will actually have to look at our workforce."

The budget will be cut by $19.3 million in 2012-13, $31.8 million in 2013-14, $44.5 million in 2014-15 and $57.1 million in 2015-16.

The cuts will have to be balanced against an enterprise bargaining agreement, brokered in March 2011, allowing for a 17 per cent increase in police base salaries over three years.

Mr Weatherill said the Government could not be criticised about the resources it had given to police. "I can rule out any cut in police numbers. In fact police numbers will grow," he said.

"It's gone from 3700 to 4500 at present and will be 4700 by 2016." Mr O'Brien said the State Government was committed to recruiting 313 additional police officers by 2016.

"We are working with SAPOL to ensure any savings do not impact on frontline services," Mr O'Brien said.

Family First MLC and former police minister Rob Brokenshire said savings targets would likely be met by delaying recruitment, rather than sacking officers.

"I cannot see how, with cuts of that magnitude, that there will not be a significant impact on frontline operation police services," he said.

"Above replacement of those retiring, there will be no recruitment in the next two years. Worse than that could be a net depletion of police numbers due to the budget cuts being so dramatic that they simply can't replace those retiring."

Mr O'Connell said he would be disappointed if the budget cuts prevented the Commissioner from establishing a Police Victims Unit, which he had previously flagged.

Budget and Finance Committee chairman Rob Lucas said police would need to look at both officer and staff numbers to meet the budget cuts.

"For the first time today a police commissioner has confirmed a reduction in total police numbers," he said.