There were some talks (not by government officials) that Mozambique should be partitioned with the area north of the Zambezi being a separate country. Below is a breakdown of the territory's population by race in 1960.
In 1960 the territory's four southern districts had 2,368,518 Africans or 37% of the total African population.
Manica & Sofala 751,491
Gaza 664,566
Inhambane 577,495
Lourenco Marques 374,966
In 1960 the territory had a total 97,268 whites, of these 77,185 or 80% were located in the four Southern Districts:
White Population in 1960:
Lourenco Marques 48,182
Manica & Sofala 19,668
Gaza 7,422
Inhambane 1,913
Total: 77,185
67% of the Mixed-Race Mestico Population lived in the Southern districts
Lourenco Marques 9,631
Manica & Sofala 5,150
Inhambane 3,565
Gaza 2,676
Total: 21,022
73% of the Indian Population lived in the South
Lourenco Marques 7,592
Manica & Sofala 3,734
Inhambane 752
Gaza 483
Total: 12,561
99% of the Chinese population lived in the South, overwhelmingly in Beira and Lourenco Marques
Chinese Population in 1960
Manica & Sofala 1,027
Lourenco Marques 992
Inhambane 47
Gaza 3
Total: 2,069
In the North the White Population was as follows:
Mocambique (Nampula District) 8,074
Zambezia 7,436
Tete 2,169
Cabo Delgado 1,482
Niassa 922
Total: 20,083
The Mestico Population
Zambezia 4,337
Mocambique 2,593
Tete 1,806
Cabo Delgado 1,458
Niassa 249
Total: 10,443
The Indian Population
Mocambique 2,179
Zambezia 1,325
Cabo Delgado 683
Tete 356
Niassa 139
Total: 4,682
The Chinese Population
Cabo Delgado 10
Mocambique 8
Zambezia 8
Tete 3
Niassa 0
Total: 29
When FRELIMO began its guerilla operations against the Portuguese in September 1964 they were launched from Tanzania with operations in Niassa and Cabo Delgado districts. These regions were the furthest from white settlement, making the regions easy to infiltrate. These regions had few roads or infrastructure of any kind. To counter FRELIMO, the Portuguese began paying attention to this neglected region, building roads, airfields, railways and purposely settling thousands of peasants from the Azores and Madeira in the late 1960s and early 1970s. The Nacala to Vila Cabral railway was completed in 1969 and it was hoped that this would stimulate development in the region. The growing investment and spending in the region attracted a large number of Portuguese settlers, particularly poorer ones as many went into business selling supplies to the Portuguese military. Nampula in particular experienced a boom in population as it surpassed Beira in population by 1970.
In 1970 the Portuguese military launched its largest offensive ever, known as Operation Gordion Knot. It was largely successful in removing FRELIMO from Niassa and Cabo Delgado, however their forces were only temporarily weakened as they slipped through Zambia and began operations in Tete district. Here their primary objective was the Cabora Bassa dam on the Zambezi River. FRELIMO failed to thwart the completion of the dam, however they did manage to tie down Portuguese troops in the region. In addition, troops were needed in the North to prevent FRELIMO incursions from Tanzania.
Those who proposed dividing Mozambique did so because it would keep the vital Beira and Lourenco Marques rail corridors along with the principal European settlements. Most of the industry was also located in these regions, keep in mind that the country had Africa's fourth largest industrial output in 1974. In addition, it would be protected by Rhodesia and South Africa to the West. The hostile frontier would be far more limited.
By 1974, there were around 250-300,000 Europeans in Mozambique, perhaps 100,000 Mesticos and 35,000 Indians and Chinese out of a total population of 9 million. In the four districts South of the Zambezi there were some 3.2 million Africans in 1970. If you include the Tete district south of the Zambezi to include the strategic Cabora Bassa generators, there would be a population of 4 million by 1974.