THE Cambodian Government has massed 20,000 troops from eight provinces to fight the Khmer Rouge in what is being called the largest dry season offensive against the guerillas in recent years. But military observers are watching with cautious optimism. 'Never has the Government amassed so many troops or been as prepared logistically,' said a Western military analyst, who estimated the Khmer Rouge had fewer than 1,500 fighters in Cambodia's northwestern provinces. 'When you see the balance of forces, it is clear the Royal Cambodian Armed Forces should reach their intended targets,' he said. 'But mathematical equations mean little in guerilla warfare.' In an intensive build-up that began about mid-December, the Government sent a number of divisions from Siem Reap, Pursat, Kampong Cham, Kampong Chhnang and Kampong Thom provinces to those of Banteay Meanchaey and Battambang. About 60 T54 Czech-made tanks and six fighter jets from Israel were also being deployed for the battle, according to Thai military sources. The primary aim appeared to be the capture of Pailin in Battambang, Klar Nap village in Banteay Meanchaey and An Sea Pass in Preach Vihear. But a military analyst said the Government was being cautious this year to avoid repeating the mistakes of the past two years, when they took but quickly lost both Pailin and Anlong Veng to guerillas. 'They are better prepared this year. They've learned their lessons,' he said. The dry season offensive - in the form this time of a slow push - was already underway, heading for the northwestern Khmer Rouge strongholds of Klar Nap and Malai Mountain, and for Pailin. The analyst added the prime targets would almost certainly be captured, though with heavy casualties. Though the Government has provided few reliable statistics of forces already injured or killed, a doctor in the Phnom Penh military hospital said on Thursday that the number of patients had climbed from 700 at the start of the year to 887. 'Eighty per cent of them are soldiers suffering from mine explosions and gun wounds from intensive fighting between troops and the Khmer Rouge,' said Dr Kao Try. Observers predicted capturing the bases would be less difficult than holding on to them during the rainy season. 'They have to reach their targets and consolidate their positions before the dry season is finished,' said a Western military source, adding villagers in the northwest had been recruited to help the armed forces repair roads almost as soon as Khmer Rouge ground had been captured. 'They cannot get stuck. They cannot cut their supply lines,' he said. The Khmer Rouge rebels are expected to give up their bases with little resistance and, as in previous years, to counter-attack during the rainy season when the Government faces difficulties transporting heavy equipment and moving troops.