DACCA, PAKISTAN, June 26. - Food scarcities are becoming serious in parts of East Pakistan, cash is short in rural areas, jute factories are badly crippled and key road and rail communications continue to be disrupted by guerrillas.

Nonetheless, most foreign economic experts here are convinced that the government is willing, at least for the immediate future, to pay the severe economic price of supporting its army's occupation of the eastern region, which has been badly damaged during the effort to suppress the Bengali autonomy movement.

Informed foreign sources report that their field trips have turned tip food shortages in some areas that could become grave unless the disrupted transportation system improved markedly.

One problem area is the northwest, normally a rice- surplus region that supplies neighboring districts. The Foreign economists say the northwest is desolate, with few farmers visible. Most have apparently fled to India to escape the Pakistani Army, which has been trying to suppress the Bengalis since March 25.

DESTROYED, LOOTED, REMOVED

Food stocks in the northwest have been either destroyed, looted or taken out of the country, the foreign sources said. The situation has not reached the starvation level, they added, but people do not have enough to eat and the real problem will arise in two or three months. "Right now," all economist said, "there are more likely a lot of hungry people than a lot of dead people."

The experts said that East Pakistan as a whole had a two-month supply of food grain and that the problem was distributing it to the deficit areas.

The railroad from Chittagong, East Pakistan's major port, to Dacca is still cut and guerrilla activity in the area is reported to be fairly persistent. The line normally carries 70 percent of the food grains imported by East Pakistan. Major road bridges have also been blown.

The region's usual rice deficit is about two million tons a year; this year it will probably be around three million.

DOCK LABORERS HAVE FLED

Apart from the transport mess, ports such as Chittagong and Chalna are also severely hampered by a lack of warehouse space and by labor shortages because much of the work force has fled to the interior or to India. Because of the port congestion, the United States, which normally supplies East Pakistan with up to a million tons of food grains a year, has temporarily suspended shipments.

The other major food-scarce area is the delta region of the Bay of Bengal that was devastated by the cyclone last November that killed several hundred thousand people and destroyed most of the rich rice crop there. Food stocks are low on the islands and in the coastal areas, although conditions are not as critical as was originally feared because some relief food has been delivered .

Nevertheless, the foreign sources said, unless the distribution system improves, the region could become a famine area.

The Khulna district in the Ganges Delta also has a food problem, the sources said, because many Hindu farmers and farm laborers have fled. The minority Hindus have been particular targets of the army, which pictures them as agents of India and enemies of this Moslem nation. Another unknown is the long-run impact of the exodus of the six million Bengalis who have fled to India. Their departure, which has cut food output and industrial production, has also reduced consumption.

Even in areas where rice is in reasonably good supply, cash is short and many villagers cannot afford to buy enough, even at the reduced prices at which the fleeing Hindu farmers are selling it.

The main reason for the shortage of money is that the Government's rural public-works program has been almost halted. Laborers who used to make 60 cents a day building roads, irrigation canals and dikes are jobless. All development work has stopped. Government agricultural technicians and private irrigation-well contractors are afraid to go into the interior. Foreign consultants and engineers are killing time in their Dacca offices.. Government offices, though open, are short of staff and doing no planning work.

Jute factories are operating at a fraction of their former levels. The eastern region's jute, one of the mainstays of the national economy, is Pakistan's biggest export and earner of foreign exchange.

This was the economic picture found by the World Bank team that toured East' Pakistan recently to study the prospects of peace and stability as a requisite to the resumption of full-scale aid.

The team, described by the foreign economists here as shocked and disconsolate was reported to have recommended that aid be withheld until a viable political solution was found and a realistic development plan was prepared by the martial-law government.

The World Bank coordinates an Donation consortium that has been supplying about $500-million a year in aid on which Pakistan is heavily dependent. The United States channels most of its aid - about $200-million a year - through the consortium.

How long Pakistan will continue to support army activities in East Pakistan without the foreign aid is a subject of widespread discussion in the foreign community here.

Although foreign-exchange reserves are low, the situation is not quite as crippling as had been assumed. One reason is Pakistan's unilateral declaration of a moratorium on payments on her huge international debt. Another is that since the fighting began almost no imports have entered East Pakistan so the government has saved foreign exchange. Finally, by coincidence, high inventories of raw materials for manufacturing had been accumulated in West Pakistan before the trouble started.

In sum, the foreign economists feel that though Pakistan's economic position verges on the desperate, it does not necessarily presage an early end of the occupation of the east.