Economics may smooth path from Rhodesia to Zimbabwe

British traders, initially alarmed that avowed Marxist Robert Mugabe is about to assume power in Rhodesia, are moving into a mood of cautious optimism. The feeling is growing here that there will be plenty of business to be done with the new black government in Salisbury.

The reassessments follow to sets of political signals:

* Assurances by Mr. Mugabe that Zimbabwe (as the independent state will be called) will not plunge into a frenzy of state socialism but will operate a mixed economy.

* Indications from South Africa that Prime Minister Pieter W. Botha wants a viable economic relationship with Mr. Mugabe's regime.

After sortees to Salisbury in the weeks before the election that produced that Mugabe victory, British industrial leaders report that business worth #:200 million ($448 million) in 1980 may be possible.

Delegations from the Confederation of British Industry and the Institute of Director visited Salisbury when it was doubted that Mr. Mugabe would be able to muster enough votes to gain an outright majority.

Now that the Zimbabwe African National Union-Patriotic Front leader has notched up this stunning victory, delegation members have to decide whether the impressions gained on tour to Rhodesia are still valid.

Oil executives who made the trip report that Mr. Mugabe apparently does not intend to place obstacles in the path of petroleum trade with Zimbabwe.

Strong suggestions that the incoming government will not nationalize mining operations are stirring hopes that foreign companies will continue to benefit from mineral exports.

Mugabe officials says companies will be able to export their profits under agreed rules. They insist, however, that wages paid to black workers will have to rise if the companies are not to come into conflict with the black political administration.

Entrepreneurs hopeful of gaining from Rhodesia's transition to full legal independence as Zimbabwe stress that one essential prerequisite is a stable relationship between the new country and South Africa.

Reports reaching the British government suggest that Premier Botha does not wish to confront Zimbabwe militarily or to turn an economic cold shoulder toward it. The reports note that Mr. Botha is receiving advice that an economically weak Zimbabwe would be a greater danger to South Africa than one undergoing controlled economic growth.

Mr. Mugabe has spoken with reserve of the need for a continuing economic and commercial relationship with South Africa. But his officials go further, indicating privately that a merger of interests in the economic sphere will be inevitable.

The Mugabe government will have to make an early decision on whether to take over the #:2 billion ($4.8 billion) five-year development plan drawn up by the former Muzorewa government or to modify it.

Zimbabwe's economic recovery after seven years of war will depend heavily on sticking to a coherent program of development, and foreign aid will be crucial.

Traders in Britain believe the need for economic support from the West will help to moderate what they see as Mr. Mugabe's natural tendency to prefer socialist solutions. They hope the new government will not make too many changes in the development plan.

Officials British assessments note that much will depend on the amount of influence Joshua Nkomo, runner-up in the election and newly designated home affairs minister, will be able to wield in the Mugabe government.

Mr. Nkomo is strong on economic contacts with the West, despite the close political ties he fostered with the Soviet Union.

For the moment, most British companies with their sights on profits in Zimbabwe are keeping a low profile. Many of the larger firms have installed representatives in Salisbury to prepare for the moment when Mr. Mugabe, once in office, gives the expected green light for commercial contacts with foreign traders to move into full swing.

British firms in such fields as vehicle sales and engineering realize that they will face stiff competition from other Europeans as well as from the Japanese.

East European traders, including the East Germans, are showing keen interest in acquiring a slice of the market, and their British counterparts will have to battle hard to hold their own against keen competition.