Assaults on teachers and fellow pupils accounted for 84 out of 291 lasting exclusions - almost 30 per cent, and up 8 per cent on the previous year, according to analysis of the Assembly government's latest statistics.
Violence was the main reason for the last-resort disciplinary action, followed by rule-breaking and threatening behaviour. The proportion of pupils excluded for carrying an offensive weapon was also up slightly on 2005-06 at 3.4 per cent.
But a rise in school and local authority managed exclusions - a practice condemned by experts earlier this year - means permanent exclusion is down by a third overall, from 438 in 2005-06 to 291 in 2006-07.
The latest count was released by the government six months after the conclusions of the biggest review into pupil behaviour and attendance in Wales were published. The report, by the National Behaviour and Attendance Review (NBAR) group, said there should be zero-tolerance of pupil violence.
Professor Ken Reid, the group's chair, said schools were right to take a stand on violence and aggression. "You can never doubt the need for teachers to exclude pupils who are violent," he said.
The exclusion expert renewed calls for the Assembly government to strengthen and clarify guidance on the use of physical restraint, a major recommendation of the report.
"Teachers are confused and concerned that if they intervene in a physical situation, they end up receiving the blame," he said.
An increase in pupil violence across the UK, including a spate of teenage stabbings and shootings, has also prompted the government to consider giving heads the legal right to search pupils suspected of carrying weapons, similar to powers recently introduced in England. Consultation on a change to the law will begin next autumn.
The sharp drop in the number of permanent exclusions was regarded with suspicion by some teaching unions this week, which said the figures were distorted.
But the apparent reason, a hike in managed exclusions, in which parents of badly behaved children agree with schools and local authorities that a move to another school or tutoring is the best option, was criticised in the NBAR report.
Managed moves can be a fresh start for troubled pupils, but so-called "negotiated" exclusions are also contentious because of reports of teenagers "roaming streets" with no educational provision turning to a life of crime.
The latest figures were delayed for six months so that officials could investigate their reliability because of an increase in managed moves, which are more prevalent in some local authorities than others.
Some 85 permanent exclusions resulted in pupils being tutored at home, the most popular recourse in 2006-07.
Local authorities and schools are increasingly under pressure to find alternative solutions to permanent exclusion, and schools with high exclusion rates have been threatened with extra scrutiny by inspectors.
But the latest statistics do show that the number of excluded pupils without educational provision fell to just 14, the lowest since detailed records began in 2002-3.
Exclusion rates in Welsh secondaries due to the rise in managed moves are now below those in England for the first time, with 1.8 pupils per 1,000, compared with 2.4 permanently excluded during the year.
But the number of fixed-term exclusions in primaries will cause concern - 47 reception pupils were barred from school for a five-day period during the year.
NBAR will make recommendations to the Assembly government for new Wales- only legislation on exclusions by the end of March next year.
EXCLUSIONS IN 2006-7
4,898 Pupils given fixed-term exclusions in Year 10
0 Permanent exclusions in Rhondda Cynon Taff
56 Permanent exclusions in Cardiff
1,712 Boys excluded for a fixed-term period
535 Girls excluded for a fixed period of five days
22 Primary pupils permanently excluded.